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SF bug #1202395: Description of string.lstrip() needs improvement Clarify the role of the chars argument in the strip() methods.
author Raymond Hettinger <python@rcn.com>
date Tue, 31 May 2005 10:28:07 +0000
parents 672e5f65172c
children f89cbe69db63 1873e8af5a8a
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1 \section{Built-in Types \label{types}}
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2
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3 The following sections describe the standard types that are built into
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4 the interpreter. Historically, Python's built-in types have differed
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5 from user-defined types because it was not possible to use the built-in
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6 types as the basis for object-oriented inheritance. With the 2.2
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7 release this situation has started to change, although the intended
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8 unification of user-defined and built-in types is as yet far from
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9 complete.
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10
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11 The principal built-in types are numerics, sequences, mappings, files
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12 classes, instances and exceptions.
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13 \indexii{built-in}{types}
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14
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15 Some operations are supported by several object types; in particular,
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16 practically all objects can be compared, tested for truth value,
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17 and converted to a string (with the \code{`\textrm{\ldots}`} notation,
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18 the equivalent \function{repr()} function, or the slightly different
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19 \function{str()} function). The latter
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20 function is implicitly used when an object is written by the
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21 \keyword{print}\stindex{print} statement.
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22 (Information on \ulink{\keyword{print} statement}{../ref/print.html}
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23 and other language statements can be found in the
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24 \citetitle[../ref/ref.html]{Python Reference Manual} and the
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25 \citetitle[../tut/tut.html]{Python Tutorial}.)
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26
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27
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28 \subsection{Truth Value Testing\label{truth}}
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29
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30 Any object can be tested for truth value, for use in an \keyword{if} or
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31 \keyword{while} condition or as operand of the Boolean operations below.
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32 The following values are considered false:
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33 \stindex{if}
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34 \stindex{while}
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35 \indexii{truth}{value}
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36 \indexii{Boolean}{operations}
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37 \index{false}
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38
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39 \begin{itemize}
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40
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41 \item \code{None}
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42 \withsubitem{(Built-in object)}{\ttindex{None}}
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43
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44 \item \code{False}
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45 \withsubitem{(Built-in object)}{\ttindex{False}}
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46
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47 \item zero of any numeric type, for example, \code{0}, \code{0L},
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48 \code{0.0}, \code{0j}.
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49
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50 \item any empty sequence, for example, \code{''}, \code{()}, \code{[]}.
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51
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52 \item any empty mapping, for example, \code{\{\}}.
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53
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54 \item instances of user-defined classes, if the class defines a
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55 \method{__nonzero__()} or \method{__len__()} method, when that
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56 method returns the integer zero or \class{bool} value
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57 \code{False}.\footnote{Additional
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58 information on these special methods may be found in the
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59 \citetitle[../ref/ref.html]{Python Reference Manual}.}
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60
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61 \end{itemize}
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62
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63 All other values are considered true --- so objects of many types are
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64 always true.
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65 \index{true}
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66
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67 Operations and built-in functions that have a Boolean result always
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68 return \code{0} or \code{False} for false and \code{1} or \code{True}
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69 for true, unless otherwise stated. (Important exception: the Boolean
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70 operations \samp{or}\opindex{or} and \samp{and}\opindex{and} always
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71 return one of their operands.)
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72 \index{False}
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73 \index{True}
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74
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75 \subsection{Boolean Operations \label{boolean}}
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76
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77 These are the Boolean operations, ordered by ascending priority:
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78 \indexii{Boolean}{operations}
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79
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80 \begin{tableiii}{c|l|c}{code}{Operation}{Result}{Notes}
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81 \lineiii{\var{x} or \var{y}}
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82 {if \var{x} is false, then \var{y}, else \var{x}}{(1)}
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83 \lineiii{\var{x} and \var{y}}
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84 {if \var{x} is false, then \var{x}, else \var{y}}{(1)}
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85 \hline
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86 \lineiii{not \var{x}}
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87 {if \var{x} is false, then \code{True}, else \code{False}}{(2)}
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88 \end{tableiii}
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89 \opindex{and}
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90 \opindex{or}
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91 \opindex{not}
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92
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93 \noindent
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94 Notes:
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95
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96 \begin{description}
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97
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98 \item[(1)]
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99 These only evaluate their second argument if needed for their outcome.
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100
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101 \item[(2)]
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102 \samp{not} has a lower priority than non-Boolean operators, so
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103 \code{not \var{a} == \var{b}} is interpreted as \code{not (\var{a} ==
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104 \var{b})}, and \code{\var{a} == not \var{b}} is a syntax error.
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105
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106 \end{description}
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107
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108
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109 \subsection{Comparisons \label{comparisons}}
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110
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111 Comparison operations are supported by all objects. They all have the
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112 same priority (which is higher than that of the Boolean operations).
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113 Comparisons can be chained arbitrarily; for example, \code{\var{x} <
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114 \var{y} <= \var{z}} is equivalent to \code{\var{x} < \var{y} and
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115 \var{y} <= \var{z}}, except that \var{y} is evaluated only once (but
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116 in both cases \var{z} is not evaluated at all when \code{\var{x} <
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117 \var{y}} is found to be false).
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118 \indexii{chaining}{comparisons}
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119
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120 This table summarizes the comparison operations:
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121
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122 \begin{tableiii}{c|l|c}{code}{Operation}{Meaning}{Notes}
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123 \lineiii{<}{strictly less than}{}
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124 \lineiii{<=}{less than or equal}{}
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125 \lineiii{>}{strictly greater than}{}
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126 \lineiii{>=}{greater than or equal}{}
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127 \lineiii{==}{equal}{}
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128 \lineiii{!=}{not equal}{(1)}
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129 \lineiii{<>}{not equal}{(1)}
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130 \lineiii{is}{object identity}{}
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131 \lineiii{is not}{negated object identity}{}
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132 \end{tableiii}
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133 \indexii{operator}{comparison}
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134 \opindex{==} % XXX *All* others have funny characters < ! >
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135 \opindex{is}
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136 \opindex{is not}
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137
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138 \noindent
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139 Notes:
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140
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141 \begin{description}
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142
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143 \item[(1)]
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144 \code{<>} and \code{!=} are alternate spellings for the same operator.
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145 \code{!=} is the preferred spelling; \code{<>} is obsolescent.
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146
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147 \end{description}
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148
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149 Objects of different types, except different numeric types and different string types, never
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150 compare equal; such objects are ordered consistently but arbitrarily
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151 (so that sorting a heterogeneous array yields a consistent result).
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152 Furthermore, some types (for example, file objects) support only a
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153 degenerate notion of comparison where any two objects of that type are
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154 unequal. Again, such objects are ordered arbitrarily but
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155 consistently. The \code{<}, \code{<=}, \code{>} and \code{>=}
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156 operators will raise a \exception{TypeError} exception when any operand
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157 is a complex number.
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158 \indexii{object}{numeric}
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159 \indexii{objects}{comparing}
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160
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161 Instances of a class normally compare as non-equal unless the class
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162 \withsubitem{(instance method)}{\ttindex{__cmp__()}}
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163 defines the \method{__cmp__()} method. Refer to the
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164 \citetitle[../ref/customization.html]{Python Reference Manual} for
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165 information on the use of this method to effect object comparisons.
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166
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167 \strong{Implementation note:} Objects of different types except
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168 numbers are ordered by their type names; objects of the same types
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169 that don't support proper comparison are ordered by their address.
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170
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171 Two more operations with the same syntactic priority,
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172 \samp{in}\opindex{in} and \samp{not in}\opindex{not in}, are supported
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173 only by sequence types (below).
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174
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175
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176 \subsection{Numeric Types \label{typesnumeric}}
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177
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178 There are four distinct numeric types: \dfn{plain integers},
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179 \dfn{long integers},
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180 \dfn{floating point numbers}, and \dfn{complex numbers}.
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181 In addition, Booleans are a subtype of plain integers.
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182 Plain integers (also just called \dfn{integers})
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183 are implemented using \ctype{long} in C, which gives them at least 32
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184 bits of precision. Long integers have unlimited precision. Floating
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185 point numbers are implemented using \ctype{double} in C. All bets on
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186 their precision are off unless you happen to know the machine you are
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187 working with.
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188 \obindex{numeric}
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189 \obindex{Boolean}
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190 \obindex{integer}
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191 \obindex{long integer}
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192 \obindex{floating point}
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193 \obindex{complex number}
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194 \indexii{C}{language}
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195
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196 Complex numbers have a real and imaginary part, which are each
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197 implemented using \ctype{double} in C. To extract these parts from
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198 a complex number \var{z}, use \code{\var{z}.real} and \code{\var{z}.imag}.
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199
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200 Numbers are created by numeric literals or as the result of built-in
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201 functions and operators. Unadorned integer literals (including hex
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202 and octal numbers) yield plain integers unless the value they denote
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203 is too large to be represented as a plain integer, in which case
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204 they yield a long integer. Integer literals with an
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205 \character{L} or \character{l} suffix yield long integers
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206 (\character{L} is preferred because \samp{1l} looks too much like
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207 eleven!). Numeric literals containing a decimal point or an exponent
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208 sign yield floating point numbers. Appending \character{j} or
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209 \character{J} to a numeric literal yields a complex number with a
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210 zero real part. A complex numeric literal is the sum of a real and
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211 an imaginary part.
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212 \indexii{numeric}{literals}
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213 \indexii{integer}{literals}
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214 \indexiii{long}{integer}{literals}
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215 \indexii{floating point}{literals}
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216 \indexii{complex number}{literals}
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217 \indexii{hexadecimal}{literals}
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218 \indexii{octal}{literals}
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219
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220 Python fully supports mixed arithmetic: when a binary arithmetic
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221 operator has operands of different numeric types, the operand with the
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222 ``narrower'' type is widened to that of the other, where plain
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223 integer is narrower than long integer is narrower than floating point is
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224 narrower than complex.
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225 Comparisons between numbers of mixed type use the same rule.\footnote{
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226 As a consequence, the list \code{[1, 2]} is considered equal
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227 to \code{[1.0, 2.0]}, and similarly for tuples.
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228 } The constructors \function{int()}, \function{long()}, \function{float()},
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229 and \function{complex()} can be used
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230 to produce numbers of a specific type.
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231 \index{arithmetic}
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232 \bifuncindex{int}
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233 \bifuncindex{long}
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234 \bifuncindex{float}
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235 \bifuncindex{complex}
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236
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237 All numeric types (except complex) support the following operations,
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238 sorted by ascending priority (operations in the same box have the same
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239 priority; all numeric operations have a higher priority than
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240 comparison operations):
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241
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242 \begin{tableiii}{c|l|c}{code}{Operation}{Result}{Notes}
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243 \lineiii{\var{x} + \var{y}}{sum of \var{x} and \var{y}}{}
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244 \lineiii{\var{x} - \var{y}}{difference of \var{x} and \var{y}}{}
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245 \hline
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246 \lineiii{\var{x} * \var{y}}{product of \var{x} and \var{y}}{}
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247 \lineiii{\var{x} / \var{y}}{quotient of \var{x} and \var{y}}{(1)}
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248 \lineiii{\var{x} \%{} \var{y}}{remainder of \code{\var{x} / \var{y}}}{(4)}
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249 \hline
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250 \lineiii{-\var{x}}{\var{x} negated}{}
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251 \lineiii{+\var{x}}{\var{x} unchanged}{}
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252 \hline
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253 \lineiii{abs(\var{x})}{absolute value or magnitude of \var{x}}{}
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254 \lineiii{int(\var{x})}{\var{x} converted to integer}{(2)}
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255 \lineiii{long(\var{x})}{\var{x} converted to long integer}{(2)}
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256 \lineiii{float(\var{x})}{\var{x} converted to floating point}{}
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257 \lineiii{complex(\var{re},\var{im})}{a complex number with real part \var{re}, imaginary part \var{im}. \var{im} defaults to zero.}{}
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258 \lineiii{\var{c}.conjugate()}{conjugate of the complex number \var{c}}{}
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259 \lineiii{divmod(\var{x}, \var{y})}{the pair \code{(\var{x} / \var{y}, \var{x} \%{} \var{y})}}{(3)(4)}
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260 \lineiii{pow(\var{x}, \var{y})}{\var{x} to the power \var{y}}{}
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261 \lineiii{\var{x} ** \var{y}}{\var{x} to the power \var{y}}{}
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262 \end{tableiii}
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263 \indexiii{operations on}{numeric}{types}
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264 \withsubitem{(complex number method)}{\ttindex{conjugate()}}
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265
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266 \noindent
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267 Notes:
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268 \begin{description}
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269
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270 \item[(1)]
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271 For (plain or long) integer division, the result is an integer.
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272 The result is always rounded towards minus infinity: 1/2 is 0,
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273 (-1)/2 is -1, 1/(-2) is -1, and (-1)/(-2) is 0. Note that the result
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274 is a long integer if either operand is a long integer, regardless of
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275 the numeric value.
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276 \indexii{integer}{division}
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277 \indexiii{long}{integer}{division}
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278
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279 \item[(2)]
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280 Conversion from floating point to (long or plain) integer may round or
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281 truncate as in C; see functions \function{floor()} and
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282 \function{ceil()} in the \refmodule{math}\refbimodindex{math} module
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283 for well-defined conversions.
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284 \withsubitem{(in module math)}{\ttindex{floor()}\ttindex{ceil()}}
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285 \indexii{numeric}{conversions}
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286 \indexii{C}{language}
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287
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288 \item[(3)]
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289 See section \ref{built-in-funcs}, ``Built-in Functions,'' for a full
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290 description.
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291
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292 \item[(4)]
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293 Complex floor division operator, modulo operator, and \function{divmod()}.
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294
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295 \deprecated{2.3}{Instead convert to float using \function{abs()}
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296 if appropriate.}
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297
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298 \end{description}
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299 % XXXJH exceptions: overflow (when? what operations?) zerodivision
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300
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301 \subsubsection{Bit-string Operations on Integer Types \label{bitstring-ops}}
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302 \nodename{Bit-string Operations}
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303
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304 Plain and long integer types support additional operations that make
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305 sense only for bit-strings. Negative numbers are treated as their 2's
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306 complement value (for long integers, this assumes a sufficiently large
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307 number of bits that no overflow occurs during the operation).
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308
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309 The priorities of the binary bit-wise operations are all lower than
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310 the numeric operations and higher than the comparisons; the unary
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311 operation \samp{\~} has the same priority as the other unary numeric
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312 operations (\samp{+} and \samp{-}).
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313
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314 This table lists the bit-string operations sorted in ascending
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315 priority (operations in the same box have the same priority):
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316
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317 \begin{tableiii}{c|l|c}{code}{Operation}{Result}{Notes}
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318 \lineiii{\var{x} | \var{y}}{bitwise \dfn{or} of \var{x} and \var{y}}{}
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319 \lineiii{\var{x} \^{} \var{y}}{bitwise \dfn{exclusive or} of \var{x} and \var{y}}{}
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320 \lineiii{\var{x} \&{} \var{y}}{bitwise \dfn{and} of \var{x} and \var{y}}{}
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321 % The empty groups below prevent conversion to guillemets.
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322 \lineiii{\var{x} <{}< \var{n}}{\var{x} shifted left by \var{n} bits}{(1), (2)}
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323 \lineiii{\var{x} >{}> \var{n}}{\var{x} shifted right by \var{n} bits}{(1), (3)}
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324 \hline
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325 \lineiii{\~\var{x}}{the bits of \var{x} inverted}{}
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326 \end{tableiii}
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327 \indexiii{operations on}{integer}{types}
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328 \indexii{bit-string}{operations}
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329 \indexii{shifting}{operations}
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330 \indexii{masking}{operations}
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331
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332 \noindent
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333 Notes:
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334 \begin{description}
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335 \item[(1)] Negative shift counts are illegal and cause a
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336 \exception{ValueError} to be raised.
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337 \item[(2)] A left shift by \var{n} bits is equivalent to
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338 multiplication by \code{pow(2, \var{n})} without overflow check.
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339 \item[(3)] A right shift by \var{n} bits is equivalent to
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340 division by \code{pow(2, \var{n})} without overflow check.
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341 \end{description}
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342
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343
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344 \subsection{Iterator Types \label{typeiter}}
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345
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346 \versionadded{2.2}
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347 \index{iterator protocol}
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348 \index{protocol!iterator}
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349 \index{sequence!iteration}
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350 \index{container!iteration over}
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351
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352 Python supports a concept of iteration over containers. This is
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353 implemented using two distinct methods; these are used to allow
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354 user-defined classes to support iteration. Sequences, described below
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355 in more detail, always support the iteration methods.
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356
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357 One method needs to be defined for container objects to provide
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358 iteration support:
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359
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360 \begin{methoddesc}[container]{__iter__}{}
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361 Return an iterator object. The object is required to support the
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362 iterator protocol described below. If a container supports
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363 different types of iteration, additional methods can be provided to
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364 specifically request iterators for those iteration types. (An
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365 example of an object supporting multiple forms of iteration would be
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366 a tree structure which supports both breadth-first and depth-first
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367 traversal.) This method corresponds to the \member{tp_iter} slot of
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368 the type structure for Python objects in the Python/C API.
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369 \end{methoddesc}
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370
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371 The iterator objects themselves are required to support the following
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372 two methods, which together form the \dfn{iterator protocol}:
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373
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374 \begin{methoddesc}[iterator]{__iter__}{}
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375 Return the iterator object itself. This is required to allow both
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376 containers and iterators to be used with the \keyword{for} and
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377 \keyword{in} statements. This method corresponds to the
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378 \member{tp_iter} slot of the type structure for Python objects in
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379 the Python/C API.
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380 \end{methoddesc}
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381
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382 \begin{methoddesc}[iterator]{next}{}
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383 Return the next item from the container. If there are no further
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384 items, raise the \exception{StopIteration} exception. This method
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385 corresponds to the \member{tp_iternext} slot of the type structure
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386 for Python objects in the Python/C API.
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387 \end{methoddesc}
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388
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389 Python defines several iterator objects to support iteration over
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390 general and specific sequence types, dictionaries, and other more
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391 specialized forms. The specific types are not important beyond their
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392 implementation of the iterator protocol.
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393
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394 The intention of the protocol is that once an iterator's
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395 \method{next()} method raises \exception{StopIteration}, it will
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396 continue to do so on subsequent calls. Implementations that
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397 do not obey this property are deemed broken. (This constraint
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398 was added in Python 2.3; in Python 2.2, various iterators are
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399 broken according to this rule.)
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400
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401 Python's generators provide a convenient way to implement the
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402 iterator protocol. If a container object's \method{__iter__()}
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parents: 29516
diff changeset
403 method is implemented as a generator, it will automatically
8807e901c526 SF bug #696777: How to make a class iterable using a member generator.
Raymond Hettinger <python@rcn.com>
parents: 29516
diff changeset
404 return an iterator object (technically, a generator object)
8807e901c526 SF bug #696777: How to make a class iterable using a member generator.
Raymond Hettinger <python@rcn.com>
parents: 29516
diff changeset
405 supplying the \method{__iter__()} and \method{next()} methods.
8807e901c526 SF bug #696777: How to make a class iterable using a member generator.
Raymond Hettinger <python@rcn.com>
parents: 29516
diff changeset
406
17658
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
407
9083
bc41e86c938c Markup nits.
Fred Drake <fdrake@acm.org>
parents: 9034
diff changeset
408 \subsection{Sequence Types \label{typesseq}}
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diff changeset
409
13967
7b7ee58901fb Document the range type, as suggested by Denis S. Otkidach
Fred Drake <fdrake@acm.org>
parents: 13933
diff changeset
410 There are six sequence types: strings, Unicode strings, lists,
14044
a905c5aa0691 As pointed out by Denis S. Otkidach <den@analyt.chem.msu.ru>, xrange()
Fred Drake <fdrake@acm.org>
parents: 13967
diff changeset
411 tuples, buffers, and xrange objects.
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diff changeset
412
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Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
413 String literals are written in single or double quotes:
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Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
414 \code{'xyzzy'}, \code{"frobozz"}. See chapter 2 of the
13933
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Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
415 \citetitle[../ref/strings.html]{Python Reference Manual} for more about
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
416 string literals. Unicode strings are much like strings, but are
34296
67f2190e1f6d SF Patch #1093896: miscellaneous doc typos
Raymond Hettinger <python@rcn.com>
parents: 34078
diff changeset
417 specified in the syntax using a preceding \character{u} character:
13933
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Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
418 \code{u'abc'}, \code{u"def"}. Lists are constructed with square brackets,
11463
17e12305973e Use \citetitle and \programopt as appropriate.
Fred Drake <fdrake@acm.org>
parents: 11183
diff changeset
419 separating items with commas: \code{[a, b, c]}. Tuples are
17e12305973e Use \citetitle and \programopt as appropriate.
Fred Drake <fdrake@acm.org>
parents: 11183
diff changeset
420 constructed by the comma operator (not within square brackets), with
17e12305973e Use \citetitle and \programopt as appropriate.
Fred Drake <fdrake@acm.org>
parents: 11183
diff changeset
421 or without enclosing parentheses, but an empty tuple must have the
30375
4aa84a8b1fe4 Fix spacing markup and other sundries.
Raymond Hettinger <python@rcn.com>
parents: 30250
diff changeset
422 enclosing parentheses, such as \code{a, b, c} or \code{()}. A single
4aa84a8b1fe4 Fix spacing markup and other sundries.
Raymond Hettinger <python@rcn.com>
parents: 30250
diff changeset
423 item tuple must have a trailing comma, such as \code{(d,)}.
15005
0cf5111bf09c Use \obindex{...} instead of \indexii{...}{type} in many places; this is
Fred Drake <fdrake@acm.org>
parents: 14710
diff changeset
424 \obindex{sequence}
0cf5111bf09c Use \obindex{...} instead of \indexii{...}{type} in many places; this is
Fred Drake <fdrake@acm.org>
parents: 14710
diff changeset
425 \obindex{string}
0cf5111bf09c Use \obindex{...} instead of \indexii{...}{type} in many places; this is
Fred Drake <fdrake@acm.org>
parents: 14710
diff changeset
426 \obindex{Unicode}
0cf5111bf09c Use \obindex{...} instead of \indexii{...}{type} in many places; this is
Fred Drake <fdrake@acm.org>
parents: 14710
diff changeset
427 \obindex{tuple}
0cf5111bf09c Use \obindex{...} instead of \indexii{...}{type} in many places; this is
Fred Drake <fdrake@acm.org>
parents: 14710
diff changeset
428 \obindex{list}
18395
1d0d3e6a3201 List constraints on xrange() objects.
Guido van Rossum <guido@python.org>
parents: 18391
diff changeset
429
1d0d3e6a3201 List constraints on xrange() objects.
Guido van Rossum <guido@python.org>
parents: 18391
diff changeset
430 Buffer objects are not directly supported by Python syntax, but can be
1d0d3e6a3201 List constraints on xrange() objects.
Guido van Rossum <guido@python.org>
parents: 18391
diff changeset
431 created by calling the builtin function
25393
f559e97a41be Remove spurious period.
Fred Drake <fdrake@acm.org>
parents: 24902
diff changeset
432 \function{buffer()}.\bifuncindex{buffer} They don't support
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63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
433 concatenation or repetition.
18395
1d0d3e6a3201 List constraints on xrange() objects.
Guido van Rossum <guido@python.org>
parents: 18391
diff changeset
434 \obindex{buffer}
1d0d3e6a3201 List constraints on xrange() objects.
Guido van Rossum <guido@python.org>
parents: 18391
diff changeset
435
1d0d3e6a3201 List constraints on xrange() objects.
Guido van Rossum <guido@python.org>
parents: 18391
diff changeset
436 Xrange objects are similar to buffers in that there is no specific
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
437 syntax to create them, but they are created using the \function{xrange()}
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
438 function.\bifuncindex{xrange} They don't support slicing,
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
439 concatenation or repetition, and using \code{in}, \code{not in},
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
440 \function{min()} or \function{max()} on them is inefficient.
15005
0cf5111bf09c Use \obindex{...} instead of \indexii{...}{type} in many places; this is
Fred Drake <fdrake@acm.org>
parents: 14710
diff changeset
441 \obindex{xrange}
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diff changeset
442
18395
1d0d3e6a3201 List constraints on xrange() objects.
Guido van Rossum <guido@python.org>
parents: 18391
diff changeset
443 Most sequence types support the following operations. The \samp{in} and
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parents:
diff changeset
444 \samp{not in} operations have the same priorities as the comparison
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parents:
diff changeset
445 operations. The \samp{+} and \samp{*} operations have the same
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parents:
diff changeset
446 priority as the corresponding numeric operations.\footnote{They must
8a306dfd9f33 Move files around to get the names to match the module names except for
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parents:
diff changeset
447 have since the parser can't tell the type of the operands.}
8a306dfd9f33 Move files around to get the names to match the module names except for
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diff changeset
448
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parents:
diff changeset
449 This table lists the sequence operations sorted in ascending priority
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diff changeset
450 (operations in the same box have the same priority). In the table,
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diff changeset
451 \var{s} and \var{t} are sequences of the same type; \var{n}, \var{i}
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diff changeset
452 and \var{j} are integers:
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diff changeset
453
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parents:
diff changeset
454 \begin{tableiii}{c|l|c}{code}{Operation}{Result}{Notes}
33688
af300403edb8 SF patch #1041364: True/False instead of 1/0 in libstdtypes.tex
Raymond Hettinger <python@rcn.com>
parents: 33448
diff changeset
455 \lineiii{\var{x} in \var{s}}{\code{True} if an item of \var{s} is equal to \var{x}, else \code{False}}{(1)}
af300403edb8 SF patch #1041364: True/False instead of 1/0 in libstdtypes.tex
Raymond Hettinger <python@rcn.com>
parents: 33448
diff changeset
456 \lineiii{\var{x} not in \var{s}}{\code{False} if an item of \var{s} is
af300403edb8 SF patch #1041364: True/False instead of 1/0 in libstdtypes.tex
Raymond Hettinger <python@rcn.com>
parents: 33448
diff changeset
457 equal to \var{x}, else \code{True}}{(1)}
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parents:
diff changeset
458 \hline
32974
fb6ffd290cfb SF patch #980695: efficient string concatenation
Raymond Hettinger <python@rcn.com>
parents: 32951
diff changeset
459 \lineiii{\var{s} + \var{t}}{the concatenation of \var{s} and \var{t}}{(6)}
24598
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Barry Warsaw <barry@python.org>
parents: 24459
diff changeset
460 \lineiii{\var{s} * \var{n}\textrm{,} \var{n} * \var{s}}{\var{n} shallow copies of \var{s} concatenated}{(2)}
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diff changeset
461 \hline
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12e146171f3d Committing patch #591250 which provides "str1 in str2" when str1 is a
Barry Warsaw <barry@python.org>
parents: 24459
diff changeset
462 \lineiii{\var{s}[\var{i}]}{\var{i}'th item of \var{s}, origin 0}{(3)}
12e146171f3d Committing patch #591250 which provides "str1 in str2" when str1 is a
Barry Warsaw <barry@python.org>
parents: 24459
diff changeset
463 \lineiii{\var{s}[\var{i}:\var{j}]}{slice of \var{s} from \var{i} to \var{j}}{(3), (4)}
28171
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Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
464 \lineiii{\var{s}[\var{i}:\var{j}:\var{k}]}{slice of \var{s} from \var{i} to \var{j} with step \var{k}}{(3), (5)}
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diff changeset
465 \hline
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diff changeset
466 \lineiii{len(\var{s})}{length of \var{s}}{}
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parents:
diff changeset
467 \lineiii{min(\var{s})}{smallest item of \var{s}}{}
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parents:
diff changeset
468 \lineiii{max(\var{s})}{largest item of \var{s}}{}
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parents:
diff changeset
469 \end{tableiii}
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parents:
diff changeset
470 \indexiii{operations on}{sequence}{types}
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parents:
diff changeset
471 \bifuncindex{len}
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diff changeset
472 \bifuncindex{min}
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diff changeset
473 \bifuncindex{max}
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diff changeset
474 \indexii{concatenation}{operation}
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diff changeset
475 \indexii{repetition}{operation}
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parents:
diff changeset
476 \indexii{subscript}{operation}
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diff changeset
477 \indexii{slice}{operation}
28171
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Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
478 \indexii{extended slice}{operation}
8730
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diff changeset
479 \opindex{in}
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parents:
diff changeset
480 \opindex{not in}
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diff changeset
481
8a306dfd9f33 Move files around to get the names to match the module names except for
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parents:
diff changeset
482 \noindent
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diff changeset
483 Notes:
8a306dfd9f33 Move files around to get the names to match the module names except for
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parents:
diff changeset
484
8a306dfd9f33 Move files around to get the names to match the module names except for
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parents:
diff changeset
485 \begin{description}
24598
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parents: 24459
diff changeset
486 \item[(1)] When \var{s} is a string or Unicode string object the
12e146171f3d Committing patch #591250 which provides "str1 in str2" when str1 is a
Barry Warsaw <barry@python.org>
parents: 24459
diff changeset
487 \code{in} and \code{not in} operations act like a substring test. In
12e146171f3d Committing patch #591250 which provides "str1 in str2" when str1 is a
Barry Warsaw <barry@python.org>
parents: 24459
diff changeset
488 Python versions before 2.3, \var{x} had to be a string of length 1.
12e146171f3d Committing patch #591250 which provides "str1 in str2" when str1 is a
Barry Warsaw <barry@python.org>
parents: 24459
diff changeset
489 In Python 2.3 and beyond, \var{x} may be a string of any length.
12e146171f3d Committing patch #591250 which provides "str1 in str2" when str1 is a
Barry Warsaw <barry@python.org>
parents: 24459
diff changeset
490
12e146171f3d Committing patch #591250 which provides "str1 in str2" when str1 is a
Barry Warsaw <barry@python.org>
parents: 24459
diff changeset
491 \item[(2)] Values of \var{n} less than \code{0} are treated as
12223
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
492 \code{0} (which yields an empty sequence of the same type as
19529
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
493 \var{s}). Note also that the copies are shallow; nested structures
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
494 are not copied. This often haunts new Python programmers; consider:
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
495
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
496 \begin{verbatim}
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
497 >>> lists = [[]] * 3
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
498 >>> lists
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
499 [[], [], []]
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
500 >>> lists[0].append(3)
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
501 >>> lists
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
502 [[3], [3], [3]]
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
503 \end{verbatim}
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
504
33899
eb979c3f14ba Mistakes in the "sequence types" page:
Armin Rigo <arigo@tunes.org>
parents: 33688
diff changeset
505 What has happened is that \code{[[]]} is a one-element list containing
eb979c3f14ba Mistakes in the "sequence types" page:
Armin Rigo <arigo@tunes.org>
parents: 33688
diff changeset
506 an empty list, so all three elements of \code{[[]] * 3} are (pointers to)
eb979c3f14ba Mistakes in the "sequence types" page:
Armin Rigo <arigo@tunes.org>
parents: 33688
diff changeset
507 this single empty list. Modifying any of the elements of \code{lists}
eb979c3f14ba Mistakes in the "sequence types" page:
Armin Rigo <arigo@tunes.org>
parents: 33688
diff changeset
508 modifies this single list. You can create a list of different lists this
eb979c3f14ba Mistakes in the "sequence types" page:
Armin Rigo <arigo@tunes.org>
parents: 33688
diff changeset
509 way:
19529
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
510
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
511 \begin{verbatim}
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
512 >>> lists = [[] for i in range(3)]
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Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
513 >>> lists[0].append(3)
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
514 >>> lists[1].append(5)
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
515 >>> lists[2].append(7)
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
516 >>> lists
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
517 [[3], [5], [7]]
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
518 \end{verbatim}
12223
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Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
519
24598
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parents: 24459
diff changeset
520 \item[(3)] If \var{i} or \var{j} is negative, the index is relative to
18416
33b4357aebb8 Fix up a few style nits -- avoid "e.g." and "i.e." -- these make
Fred Drake <fdrake@acm.org>
parents: 18395
diff changeset
521 the end of the string: \code{len(\var{s}) + \var{i}} or
8730
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parents:
diff changeset
522 \code{len(\var{s}) + \var{j}} is substituted. But note that \code{-0} is
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parents:
diff changeset
523 still \code{0}.
22241
7584b6f1afde Change Windows file.truncate() to (a) restore the original file position,
Tim Peters <tim.peters@gmail.com>
parents: 22214
diff changeset
524
24598
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Barry Warsaw <barry@python.org>
parents: 24459
diff changeset
525 \item[(4)] The slice of \var{s} from \var{i} to \var{j} is defined as
8730
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parents:
diff changeset
526 the sequence of items with index \var{k} such that \code{\var{i} <=
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parents:
diff changeset
527 \var{k} < \var{j}}. If \var{i} or \var{j} is greater than
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parents:
diff changeset
528 \code{len(\var{s})}, use \code{len(\var{s})}. If \var{i} is omitted,
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Fred Drake <fdrake@acm.org>
parents:
diff changeset
529 use \code{0}. If \var{j} is omitted, use \code{len(\var{s})}. If
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
530 \var{i} is greater than or equal to \var{j}, the slice is empty.
28171
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Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
531
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
532 \item[(5)] The slice of \var{s} from \var{i} to \var{j} with step
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
533 \var{k} is defined as the sequence of items with index
33899
eb979c3f14ba Mistakes in the "sequence types" page:
Armin Rigo <arigo@tunes.org>
parents: 33688
diff changeset
534 \code{\var{x} = \var{i} + \var{n}*\var{k}} such that
eb979c3f14ba Mistakes in the "sequence types" page:
Armin Rigo <arigo@tunes.org>
parents: 33688
diff changeset
535 $0 \leq n < \frac{j-i}{k}$. In other words, the indices
eb979c3f14ba Mistakes in the "sequence types" page:
Armin Rigo <arigo@tunes.org>
parents: 33688
diff changeset
536 are \code{i}, \code{i+k}, \code{i+2*k}, \code{i+3*k} and so on, stopping when
eb979c3f14ba Mistakes in the "sequence types" page:
Armin Rigo <arigo@tunes.org>
parents: 33688
diff changeset
537 \var{j} is reached (but never including \var{j}). If \var{i} or \var{j}
28171
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Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
538 is greater than \code{len(\var{s})}, use \code{len(\var{s})}. If
30250
830c0cd8fdb2 SF patch #797180: Bug 792656: slicing explained
Raymond Hettinger <python@rcn.com>
parents: 30095
diff changeset
539 \var{i} or \var{j} are omitted then they become ``end'' values
830c0cd8fdb2 SF patch #797180: Bug 792656: slicing explained
Raymond Hettinger <python@rcn.com>
parents: 30095
diff changeset
540 (which end depends on the sign of \var{k}). Note, \var{k} cannot
830c0cd8fdb2 SF patch #797180: Bug 792656: slicing explained
Raymond Hettinger <python@rcn.com>
parents: 30095
diff changeset
541 be zero.
28171
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Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
542
32974
fb6ffd290cfb SF patch #980695: efficient string concatenation
Raymond Hettinger <python@rcn.com>
parents: 32951
diff changeset
543 \item[(6)] If \var{s} and \var{t} are both strings, some Python
32975
9b188158181f Typo fix; use 'in-place' instead of 'inplace'
Andrew M. Kuchling <amk@amk.ca>
parents: 32974
diff changeset
544 implementations such as CPython can usually perform an in-place optimization
32974
fb6ffd290cfb SF patch #980695: efficient string concatenation
Raymond Hettinger <python@rcn.com>
parents: 32951
diff changeset
545 for assignments of the form \code{\var{s}=\var{s}+\var{t}} or
fb6ffd290cfb SF patch #980695: efficient string concatenation
Raymond Hettinger <python@rcn.com>
parents: 32951
diff changeset
546 \code{\var{s}+=\var{t}}. When applicable, this optimization makes
fb6ffd290cfb SF patch #980695: efficient string concatenation
Raymond Hettinger <python@rcn.com>
parents: 32951
diff changeset
547 quadratic run-time much less likely. This optimization is both version
fb6ffd290cfb SF patch #980695: efficient string concatenation
Raymond Hettinger <python@rcn.com>
parents: 32951
diff changeset
548 and implementation dependent. For performance sensitive code, it is
34296
67f2190e1f6d SF Patch #1093896: miscellaneous doc typos
Raymond Hettinger <python@rcn.com>
parents: 34078
diff changeset
549 preferable to use the \method{str.join()} method which assures consistent
32974
fb6ffd290cfb SF patch #980695: efficient string concatenation
Raymond Hettinger <python@rcn.com>
parents: 32951
diff changeset
550 linear concatenation performance across versions and implementations.
32975
9b188158181f Typo fix; use 'in-place' instead of 'inplace'
Andrew M. Kuchling <amk@amk.ca>
parents: 32974
diff changeset
551 \versionchanged[Formerly, string concatenation never occurred in-place]{2.4}
32974
fb6ffd290cfb SF patch #980695: efficient string concatenation
Raymond Hettinger <python@rcn.com>
parents: 32951
diff changeset
552
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
553 \end{description}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
554
10156
0f7d694bc334 Make sure all HTML pages generated from this section have reasonable
Fred Drake <fdrake@acm.org>
parents: 10147
diff changeset
555
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
556 \subsubsection{String Methods \label{string-methods}}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
557
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
558 These are the string methods which both 8-bit strings and Unicode
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
559 objects support:
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
560
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
561 \begin{methoddesc}[string]{capitalize}{}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
562 Return a copy of the string with only its first character capitalized.
32214
6478eb6ae3c0 Document string methods that are locale-dependent. Fixes #935749.
Martin v. Löwis <martin@v.loewis.de>
parents: 32197
diff changeset
563
6478eb6ae3c0 Document string methods that are locale-dependent. Fixes #935749.
Martin v. Löwis <martin@v.loewis.de>
parents: 32197
diff changeset
564 For 8-bit strings, this method is locale-dependent.
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
565 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
566
31021
21a10c3600b5 Add optional fillchar argument to ljust(), rjust(), and center() string methods.
Raymond Hettinger <python@rcn.com>
parents: 31008
diff changeset
567 \begin{methoddesc}[string]{center}{width\optional{, fillchar}}
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
568 Return centered in a string of length \var{width}. Padding is done
31021
21a10c3600b5 Add optional fillchar argument to ljust(), rjust(), and center() string methods.
Raymond Hettinger <python@rcn.com>
parents: 31008
diff changeset
569 using the specified \var{fillchar} (default is a space).
31022
845f19b145a8 Add version changed doc for addition of fillchar to ljust/rjust/center
Neal Norwitz <nnorwitz@gmail.com>
parents: 31021
diff changeset
570 \versionchanged[Support for the \var{fillchar} argument]{2.4}
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
571 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
572
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
573 \begin{methoddesc}[string]{count}{sub\optional{, start\optional{, end}}}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
574 Return the number of occurrences of substring \var{sub} in string
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
575 S\code{[\var{start}:\var{end}]}. Optional arguments \var{start} and
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
576 \var{end} are interpreted as in slice notation.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
577 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
578
21332
fbbd8a4ca7a6 Added documentation for str.decode().
Fred Drake <fdrake@acm.org>
parents: 21177
diff changeset
579 \begin{methoddesc}[string]{decode}{\optional{encoding\optional{, errors}}}
fbbd8a4ca7a6 Added documentation for str.decode().
Fred Drake <fdrake@acm.org>
parents: 21177
diff changeset
580 Decodes the string using the codec registered for \var{encoding}.
fbbd8a4ca7a6 Added documentation for str.decode().
Fred Drake <fdrake@acm.org>
parents: 21177
diff changeset
581 \var{encoding} defaults to the default string encoding. \var{errors}
fbbd8a4ca7a6 Added documentation for str.decode().
Fred Drake <fdrake@acm.org>
parents: 21177
diff changeset
582 may be given to set a different error handling scheme. The default is
fbbd8a4ca7a6 Added documentation for str.decode().
Fred Drake <fdrake@acm.org>
parents: 21177
diff changeset
583 \code{'strict'}, meaning that encoding errors raise
32459
6b1ea5c07ff7 Document that encode() and decode() raise UnicodeError
Walter Dörwald <walter@livinglogic.de>
parents: 32458
diff changeset
584 \exception{UnicodeError}. Other possible values are \code{'ignore'},
6b1ea5c07ff7 Document that encode() and decode() raise UnicodeError
Walter Dörwald <walter@livinglogic.de>
parents: 32458
diff changeset
585 \code{'replace'} and any other name registered via
6b1ea5c07ff7 Document that encode() and decode() raise UnicodeError
Walter Dörwald <walter@livinglogic.de>
parents: 32458
diff changeset
586 \function{codecs.register_error}.
21332
fbbd8a4ca7a6 Added documentation for str.decode().
Fred Drake <fdrake@acm.org>
parents: 21177
diff changeset
587 \versionadded{2.2}
32459
6b1ea5c07ff7 Document that encode() and decode() raise UnicodeError
Walter Dörwald <walter@livinglogic.de>
parents: 32458
diff changeset
588 \versionchanged[Support for other error handling schemes added]{2.3}
21332
fbbd8a4ca7a6 Added documentation for str.decode().
Fred Drake <fdrake@acm.org>
parents: 21177
diff changeset
589 \end{methoddesc}
fbbd8a4ca7a6 Added documentation for str.decode().
Fred Drake <fdrake@acm.org>
parents: 21177
diff changeset
590
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
591 \begin{methoddesc}[string]{encode}{\optional{encoding\optional{,errors}}}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
592 Return an encoded version of the string. Default encoding is the current
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
593 default string encoding. \var{errors} may be given to set a different
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
594 error handling scheme. The default for \var{errors} is
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
595 \code{'strict'}, meaning that encoding errors raise a
32459
6b1ea5c07ff7 Document that encode() and decode() raise UnicodeError
Walter Dörwald <walter@livinglogic.de>
parents: 32458
diff changeset
596 \exception{UnicodeError}. Other possible values are \code{'ignore'},
6b1ea5c07ff7 Document that encode() and decode() raise UnicodeError
Walter Dörwald <walter@livinglogic.de>
parents: 32458
diff changeset
597 \code{'replace'}, \code{'xmlcharrefreplace'}, \code{'backslashreplace'}
6b1ea5c07ff7 Document that encode() and decode() raise UnicodeError
Walter Dörwald <walter@livinglogic.de>
parents: 32458
diff changeset
598 and any other name registered via \function{codecs.register_error}.
6b1ea5c07ff7 Document that encode() and decode() raise UnicodeError
Walter Dörwald <walter@livinglogic.de>
parents: 32458
diff changeset
599 For a list of possible encodings, see section~\ref{standard-encodings}.
15332
12aec3381c94 Marc-Andre Lemburg <mal@lemburg.com> noted that the encode() string method
Fred Drake <fdrake@acm.org>
parents: 15005
diff changeset
600 \versionadded{2.0}
32459
6b1ea5c07ff7 Document that encode() and decode() raise UnicodeError
Walter Dörwald <walter@livinglogic.de>
parents: 32458
diff changeset
601 \versionchanged[Support for \code{'xmlcharrefreplace'} and
6b1ea5c07ff7 Document that encode() and decode() raise UnicodeError
Walter Dörwald <walter@livinglogic.de>
parents: 32458
diff changeset
602 \code{'backslashreplace'} and other error handling schemes added]{2.3}
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
603 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
604
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
605 \begin{methoddesc}[string]{endswith}{suffix\optional{, start\optional{, end}}}
28171
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
606 Return \code{True} if the string ends with the specified \var{suffix},
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
607 otherwise return \code{False}. With optional \var{start}, test beginning at
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
608 that position. With optional \var{end}, stop comparing at that position.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
609 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
610
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
611 \begin{methoddesc}[string]{expandtabs}{\optional{tabsize}}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
612 Return a copy of the string where all tab characters are expanded
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
613 using spaces. If \var{tabsize} is not given, a tab size of \code{8}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
614 characters is assumed.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
615 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
616
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
617 \begin{methoddesc}[string]{find}{sub\optional{, start\optional{, end}}}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
618 Return the lowest index in the string where substring \var{sub} is
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
619 found, such that \var{sub} is contained in the range [\var{start},
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
620 \var{end}). Optional arguments \var{start} and \var{end} are
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
621 interpreted as in slice notation. Return \code{-1} if \var{sub} is
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
622 not found.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
623 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
624
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
625 \begin{methoddesc}[string]{index}{sub\optional{, start\optional{, end}}}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
626 Like \method{find()}, but raise \exception{ValueError} when the
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
627 substring is not found.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
628 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
629
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
630 \begin{methoddesc}[string]{isalnum}{}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
631 Return true if all characters in the string are alphanumeric and there
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
632 is at least one character, false otherwise.
32214
6478eb6ae3c0 Document string methods that are locale-dependent. Fixes #935749.
Martin v. Löwis <martin@v.loewis.de>
parents: 32197
diff changeset
633
6478eb6ae3c0 Document string methods that are locale-dependent. Fixes #935749.
Martin v. Löwis <martin@v.loewis.de>
parents: 32197
diff changeset
634 For 8-bit strings, this method is locale-dependent.
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
635 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
636
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
637 \begin{methoddesc}[string]{isalpha}{}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
638 Return true if all characters in the string are alphabetic and there
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
639 is at least one character, false otherwise.
32214
6478eb6ae3c0 Document string methods that are locale-dependent. Fixes #935749.
Martin v. Löwis <martin@v.loewis.de>
parents: 32197
diff changeset
640
6478eb6ae3c0 Document string methods that are locale-dependent. Fixes #935749.
Martin v. Löwis <martin@v.loewis.de>
parents: 32197
diff changeset
641 For 8-bit strings, this method is locale-dependent.
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
642 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
643
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
644 \begin{methoddesc}[string]{isdigit}{}
30707
9e21e56bf5f3 Patch #825679: Clarify semantics of .isfoo on empty strings.
Martin v. Löwis <martin@v.loewis.de>
parents: 30705
diff changeset
645 Return true if all characters in the string are digits and there
9e21e56bf5f3 Patch #825679: Clarify semantics of .isfoo on empty strings.
Martin v. Löwis <martin@v.loewis.de>
parents: 30705
diff changeset
646 is at least one character, false otherwise.
32214
6478eb6ae3c0 Document string methods that are locale-dependent. Fixes #935749.
Martin v. Löwis <martin@v.loewis.de>
parents: 32197
diff changeset
647
6478eb6ae3c0 Document string methods that are locale-dependent. Fixes #935749.
Martin v. Löwis <martin@v.loewis.de>
parents: 32197
diff changeset
648 For 8-bit strings, this method is locale-dependent.
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
649 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
650
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
651 \begin{methoddesc}[string]{islower}{}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
652 Return true if all cased characters in the string are lowercase and
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
653 there is at least one cased character, false otherwise.
32214
6478eb6ae3c0 Document string methods that are locale-dependent. Fixes #935749.
Martin v. Löwis <martin@v.loewis.de>
parents: 32197
diff changeset
654
6478eb6ae3c0 Document string methods that are locale-dependent. Fixes #935749.
Martin v. Löwis <martin@v.loewis.de>
parents: 32197
diff changeset
655 For 8-bit strings, this method is locale-dependent.
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
656 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
657
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
658 \begin{methoddesc}[string]{isspace}{}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
659 Return true if there are only whitespace characters in the string and
30707
9e21e56bf5f3 Patch #825679: Clarify semantics of .isfoo on empty strings.
Martin v. Löwis <martin@v.loewis.de>
parents: 30705
diff changeset
660 there is at least one character, false otherwise.
32214
6478eb6ae3c0 Document string methods that are locale-dependent. Fixes #935749.
Martin v. Löwis <martin@v.loewis.de>
parents: 32197
diff changeset
661
6478eb6ae3c0 Document string methods that are locale-dependent. Fixes #935749.
Martin v. Löwis <martin@v.loewis.de>
parents: 32197
diff changeset
662 For 8-bit strings, this method is locale-dependent.
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
663 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
664
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
665 \begin{methoddesc}[string]{istitle}{}
30707
9e21e56bf5f3 Patch #825679: Clarify semantics of .isfoo on empty strings.
Martin v. Löwis <martin@v.loewis.de>
parents: 30705
diff changeset
666 Return true if the string is a titlecased string and there is at least one
30810
2cba0de70df6 Add list.sorted() classmethod.
Raymond Hettinger <python@rcn.com>
parents: 30750
diff changeset
667 character, for example uppercase characters may only follow uncased
30707
9e21e56bf5f3 Patch #825679: Clarify semantics of .isfoo on empty strings.
Martin v. Löwis <martin@v.loewis.de>
parents: 30705
diff changeset
668 characters and lowercase characters only cased ones. Return false
9e21e56bf5f3 Patch #825679: Clarify semantics of .isfoo on empty strings.
Martin v. Löwis <martin@v.loewis.de>
parents: 30705
diff changeset
669 otherwise.
32214
6478eb6ae3c0 Document string methods that are locale-dependent. Fixes #935749.
Martin v. Löwis <martin@v.loewis.de>
parents: 32197
diff changeset
670
6478eb6ae3c0 Document string methods that are locale-dependent. Fixes #935749.
Martin v. Löwis <martin@v.loewis.de>
parents: 32197
diff changeset
671 For 8-bit strings, this method is locale-dependent.
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
672 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
673
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
674 \begin{methoddesc}[string]{isupper}{}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
675 Return true if all cased characters in the string are uppercase and
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
676 there is at least one cased character, false otherwise.
32214
6478eb6ae3c0 Document string methods that are locale-dependent. Fixes #935749.
Martin v. Löwis <martin@v.loewis.de>
parents: 32197
diff changeset
677
6478eb6ae3c0 Document string methods that are locale-dependent. Fixes #935749.
Martin v. Löwis <martin@v.loewis.de>
parents: 32197
diff changeset
678 For 8-bit strings, this method is locale-dependent.
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
679 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
680
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
681 \begin{methoddesc}[string]{join}{seq}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
682 Return a string which is the concatenation of the strings in the
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
683 sequence \var{seq}. The separator between elements is the string
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
684 providing this method.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
685 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
686
31021
21a10c3600b5 Add optional fillchar argument to ljust(), rjust(), and center() string methods.
Raymond Hettinger <python@rcn.com>
parents: 31008
diff changeset
687 \begin{methoddesc}[string]{ljust}{width\optional{, fillchar}}
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
688 Return the string left justified in a string of length \var{width}.
31021
21a10c3600b5 Add optional fillchar argument to ljust(), rjust(), and center() string methods.
Raymond Hettinger <python@rcn.com>
parents: 31008
diff changeset
689 Padding is done using the specified \var{fillchar} (default is a
21a10c3600b5 Add optional fillchar argument to ljust(), rjust(), and center() string methods.
Raymond Hettinger <python@rcn.com>
parents: 31008
diff changeset
690 space). The original string is returned if
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
691 \var{width} is less than \code{len(\var{s})}.
31022
845f19b145a8 Add version changed doc for addition of fillchar to ljust/rjust/center
Neal Norwitz <nnorwitz@gmail.com>
parents: 31021
diff changeset
692 \versionchanged[Support for the \var{fillchar} argument]{2.4}
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
693 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
694
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
695 \begin{methoddesc}[string]{lower}{}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
696 Return a copy of the string converted to lowercase.
32214
6478eb6ae3c0 Document string methods that are locale-dependent. Fixes #935749.
Martin v. Löwis <martin@v.loewis.de>
parents: 32197
diff changeset
697
6478eb6ae3c0 Document string methods that are locale-dependent. Fixes #935749.
Martin v. Löwis <martin@v.loewis.de>
parents: 32197
diff changeset
698 For 8-bit strings, this method is locale-dependent.
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
699 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
700
23017
44637bd7f59b Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
parents: 22994
diff changeset
701 \begin{methoddesc}[string]{lstrip}{\optional{chars}}
34975
5e511ddef48b SF bug #1202395: Description of string.lstrip() needs improvement
Raymond Hettinger <python@rcn.com>
parents: 34969
diff changeset
702 Return a copy of the string with leading characters removed. The
5e511ddef48b SF bug #1202395: Description of string.lstrip() needs improvement
Raymond Hettinger <python@rcn.com>
parents: 34969
diff changeset
703 \var{chars} argument is a string specifying the set of characters
5e511ddef48b SF bug #1202395: Description of string.lstrip() needs improvement
Raymond Hettinger <python@rcn.com>
parents: 34969
diff changeset
704 to be removed. If omitted or \code{None}, the \var{chars} argument
5e511ddef48b SF bug #1202395: Description of string.lstrip() needs improvement
Raymond Hettinger <python@rcn.com>
parents: 34969
diff changeset
705 defaults to removing whitespace. The \var{chars} argument is not
5e511ddef48b SF bug #1202395: Description of string.lstrip() needs improvement
Raymond Hettinger <python@rcn.com>
parents: 34969
diff changeset
706 a prefix; rather, all combinations of its values are stripped:
5e511ddef48b SF bug #1202395: Description of string.lstrip() needs improvement
Raymond Hettinger <python@rcn.com>
parents: 34969
diff changeset
707 \begin{verbatim}
5e511ddef48b SF bug #1202395: Description of string.lstrip() needs improvement
Raymond Hettinger <python@rcn.com>
parents: 34969
diff changeset
708 >>> ' spacious '.lstrip()
5e511ddef48b SF bug #1202395: Description of string.lstrip() needs improvement
Raymond Hettinger <python@rcn.com>
parents: 34969
diff changeset
709 'spacious '
5e511ddef48b SF bug #1202395: Description of string.lstrip() needs improvement
Raymond Hettinger <python@rcn.com>
parents: 34969
diff changeset
710 >>> 'www.example.com'.lstrip('cmowz.')
5e511ddef48b SF bug #1202395: Description of string.lstrip() needs improvement
Raymond Hettinger <python@rcn.com>
parents: 34969
diff changeset
711 'example.com'
5e511ddef48b SF bug #1202395: Description of string.lstrip() needs improvement
Raymond Hettinger <python@rcn.com>
parents: 34969
diff changeset
712 \end{verbatim}
26259
60d809a25bae Document that a minor feature was added in 2.2.2. ;-(
Fred Drake <fdrake@acm.org>
parents: 26161
diff changeset
713 \versionchanged[Support for the \var{chars} argument]{2.2.2}
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
714 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
715
30750
1d92ecdf2bb1 Avoid confusing name for the 3rd argument to str.replace().
Fred Drake <fdrake@acm.org>
parents: 30737
diff changeset
716 \begin{methoddesc}[string]{replace}{old, new\optional{, count}}
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
717 Return a copy of the string with all occurrences of substring
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
718 \var{old} replaced by \var{new}. If the optional argument
30750
1d92ecdf2bb1 Avoid confusing name for the 3rd argument to str.replace().
Fred Drake <fdrake@acm.org>
parents: 30737
diff changeset
719 \var{count} is given, only the first \var{count} occurrences are
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
720 replaced.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
721 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
722
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
723 \begin{methoddesc}[string]{rfind}{sub \optional{,start \optional{,end}}}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
724 Return the highest index in the string where substring \var{sub} is
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
725 found, such that \var{sub} is contained within s[start,end]. Optional
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
726 arguments \var{start} and \var{end} are interpreted as in slice
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
727 notation. Return \code{-1} on failure.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
728 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
729
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
730 \begin{methoddesc}[string]{rindex}{sub\optional{, start\optional{, end}}}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
731 Like \method{rfind()} but raises \exception{ValueError} when the
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
732 substring \var{sub} is not found.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
733 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
734
31021
21a10c3600b5 Add optional fillchar argument to ljust(), rjust(), and center() string methods.
Raymond Hettinger <python@rcn.com>
parents: 31008
diff changeset
735 \begin{methoddesc}[string]{rjust}{width\optional{, fillchar}}
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
736 Return the string right justified in a string of length \var{width}.
31021
21a10c3600b5 Add optional fillchar argument to ljust(), rjust(), and center() string methods.
Raymond Hettinger <python@rcn.com>
parents: 31008
diff changeset
737 Padding is done using the specified \var{fillchar} (default is a space).
21a10c3600b5 Add optional fillchar argument to ljust(), rjust(), and center() string methods.
Raymond Hettinger <python@rcn.com>
parents: 31008
diff changeset
738 The original string is returned if
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
739 \var{width} is less than \code{len(\var{s})}.
31022
845f19b145a8 Add version changed doc for addition of fillchar to ljust/rjust/center
Neal Norwitz <nnorwitz@gmail.com>
parents: 31021
diff changeset
740 \versionchanged[Support for the \var{fillchar} argument]{2.4}
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
741 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
742
31206
3771ff99d5f2 Update documentations for str.rsplit() with Alex Martelli's rewrite.
Hye-Shik Chang <hyeshik@gmail.com>
parents: 31199
diff changeset
743 \begin{methoddesc}[string]{rsplit}{\optional{sep \optional{,maxsplit}}}
3771ff99d5f2 Update documentations for str.rsplit() with Alex Martelli's rewrite.
Hye-Shik Chang <hyeshik@gmail.com>
parents: 31199
diff changeset
744 Return a list of the words in the string, using \var{sep} as the
3771ff99d5f2 Update documentations for str.rsplit() with Alex Martelli's rewrite.
Hye-Shik Chang <hyeshik@gmail.com>
parents: 31199
diff changeset
745 delimiter string. If \var{maxsplit} is given, at most \var{maxsplit}
31286
3894654b4848 fix a variety of markup bugs
Fred Drake <fdrake@acm.org>
parents: 31282
diff changeset
746 splits are done, the \emph{rightmost} ones. If \var{sep} is not specified
34491
68020bd1b9e2 SF bug #1105286: Undocumented implicit strip() in split(None) string method
Raymond Hettinger <python@rcn.com>
parents: 34296
diff changeset
747 or \code{None}, any whitespace string is a separator. Except for splitting
68020bd1b9e2 SF bug #1105286: Undocumented implicit strip() in split(None) string method
Raymond Hettinger <python@rcn.com>
parents: 34296
diff changeset
748 from the right, \method{rsplit()} behaves like \method{split()} which
68020bd1b9e2 SF bug #1105286: Undocumented implicit strip() in split(None) string method
Raymond Hettinger <python@rcn.com>
parents: 34296
diff changeset
749 is described in detail below.
31199
504943c89193 Add rsplit method for str and unicode builtin types.
Hye-Shik Chang <hyeshik@gmail.com>
parents: 31022
diff changeset
750 \versionadded{2.4}
504943c89193 Add rsplit method for str and unicode builtin types.
Hye-Shik Chang <hyeshik@gmail.com>
parents: 31022
diff changeset
751 \end{methoddesc}
504943c89193 Add rsplit method for str and unicode builtin types.
Hye-Shik Chang <hyeshik@gmail.com>
parents: 31022
diff changeset
752
23017
44637bd7f59b Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
parents: 22994
diff changeset
753 \begin{methoddesc}[string]{rstrip}{\optional{chars}}
34975
5e511ddef48b SF bug #1202395: Description of string.lstrip() needs improvement
Raymond Hettinger <python@rcn.com>
parents: 34969
diff changeset
754 Return a copy of the string with trailing characters removed. The
5e511ddef48b SF bug #1202395: Description of string.lstrip() needs improvement
Raymond Hettinger <python@rcn.com>
parents: 34969
diff changeset
755 \var{chars} argument is a string specifying the set of characters
5e511ddef48b SF bug #1202395: Description of string.lstrip() needs improvement
Raymond Hettinger <python@rcn.com>
parents: 34969
diff changeset
756 to be removed. If omitted or \code{None}, the \var{chars} argument
5e511ddef48b SF bug #1202395: Description of string.lstrip() needs improvement
Raymond Hettinger <python@rcn.com>
parents: 34969
diff changeset
757 defaults to removing whitespace. The \var{chars} argument is not
5e511ddef48b SF bug #1202395: Description of string.lstrip() needs improvement
Raymond Hettinger <python@rcn.com>
parents: 34969
diff changeset
758 a suffix; rather, all combinations of its values are stripped:
5e511ddef48b SF bug #1202395: Description of string.lstrip() needs improvement
Raymond Hettinger <python@rcn.com>
parents: 34969
diff changeset
759 \begin{verbatim}
5e511ddef48b SF bug #1202395: Description of string.lstrip() needs improvement
Raymond Hettinger <python@rcn.com>
parents: 34969
diff changeset
760 >>> ' spacious '.rstrip()
5e511ddef48b SF bug #1202395: Description of string.lstrip() needs improvement
Raymond Hettinger <python@rcn.com>
parents: 34969
diff changeset
761 ' spacious'
5e511ddef48b SF bug #1202395: Description of string.lstrip() needs improvement
Raymond Hettinger <python@rcn.com>
parents: 34969
diff changeset
762 >>> 'mississippi'.rstrip('ipz')
5e511ddef48b SF bug #1202395: Description of string.lstrip() needs improvement
Raymond Hettinger <python@rcn.com>
parents: 34969
diff changeset
763 'mississ'
5e511ddef48b SF bug #1202395: Description of string.lstrip() needs improvement
Raymond Hettinger <python@rcn.com>
parents: 34969
diff changeset
764 \end{verbatim}
26259
60d809a25bae Document that a minor feature was added in 2.2.2. ;-(
Fred Drake <fdrake@acm.org>
parents: 26161
diff changeset
765 \versionchanged[Support for the \var{chars} argument]{2.2.2}
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
766 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
767
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
768 \begin{methoddesc}[string]{split}{\optional{sep \optional{,maxsplit}}}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
769 Return a list of the words in the string, using \var{sep} as the
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
770 delimiter string. If \var{maxsplit} is given, at most \var{maxsplit}
33411
136b388569a0 SF bug #901654: split method documentation can be improved
Raymond Hettinger <python@rcn.com>
parents: 33102
diff changeset
771 splits are done. (thus, the list will have at most \code{\var{maxsplit}+1}
34508
13176ed52e65 SF bug #1108303: fix .split() maxsplit doc
Raymond Hettinger <python@rcn.com>
parents: 34491
diff changeset
772 elements). If \var{maxsplit} is not specified, then there
33411
136b388569a0 SF bug #901654: split method documentation can be improved
Raymond Hettinger <python@rcn.com>
parents: 33102
diff changeset
773 is no limit on the number of splits (all possible splits are made).
136b388569a0 SF bug #901654: split method documentation can be improved
Raymond Hettinger <python@rcn.com>
parents: 33102
diff changeset
774 Consecutive delimiters are not grouped together and are
136b388569a0 SF bug #901654: split method documentation can be improved
Raymond Hettinger <python@rcn.com>
parents: 33102
diff changeset
775 deemed to delimit empty strings (for example, \samp{'1,,2'.split(',')}
33412
c09318b0090d Add missing close parenthesis.
Raymond Hettinger <python@rcn.com>
parents: 33411
diff changeset
776 returns \samp{['1', '', '2']}). The \var{sep} argument may consist of
33411
136b388569a0 SF bug #901654: split method documentation can be improved
Raymond Hettinger <python@rcn.com>
parents: 33102
diff changeset
777 multiple characters (for example, \samp{'1, 2, 3'.split(', ')} returns
33412
c09318b0090d Add missing close parenthesis.
Raymond Hettinger <python@rcn.com>
parents: 33411
diff changeset
778 \samp{['1', '2', '3']}). Splitting an empty string with a specified
34917
6bdc3426d411 Correct swapped descriptions of empty string splits.
Raymond Hettinger <python@rcn.com>
parents: 34898
diff changeset
779 separator returns \samp{['']}.
33411
136b388569a0 SF bug #901654: split method documentation can be improved
Raymond Hettinger <python@rcn.com>
parents: 33102
diff changeset
780
136b388569a0 SF bug #901654: split method documentation can be improved
Raymond Hettinger <python@rcn.com>
parents: 33102
diff changeset
781 If \var{sep} is not specified or is \code{None}, a different splitting
34491
68020bd1b9e2 SF bug #1105286: Undocumented implicit strip() in split(None) string method
Raymond Hettinger <python@rcn.com>
parents: 34296
diff changeset
782 algorithm is applied. First, whitespace characters (spaces, tabs,
68020bd1b9e2 SF bug #1105286: Undocumented implicit strip() in split(None) string method
Raymond Hettinger <python@rcn.com>
parents: 34296
diff changeset
783 newlines, returns, and formfeeds) are stripped from both ends. Then,
68020bd1b9e2 SF bug #1105286: Undocumented implicit strip() in split(None) string method
Raymond Hettinger <python@rcn.com>
parents: 34296
diff changeset
784 words are separated by arbitrary length strings of whitespace
68020bd1b9e2 SF bug #1105286: Undocumented implicit strip() in split(None) string method
Raymond Hettinger <python@rcn.com>
parents: 34296
diff changeset
785 characters. Consecutive whitespace delimiters are treated as a single
68020bd1b9e2 SF bug #1105286: Undocumented implicit strip() in split(None) string method
Raymond Hettinger <python@rcn.com>
parents: 34296
diff changeset
786 delimiter (\samp{'1 2 3'.split()} returns \samp{['1', '2', '3']}).
68020bd1b9e2 SF bug #1105286: Undocumented implicit strip() in split(None) string method
Raymond Hettinger <python@rcn.com>
parents: 34296
diff changeset
787 Splitting an empty string or a string consisting of just whitespace
34917
6bdc3426d411 Correct swapped descriptions of empty string splits.
Raymond Hettinger <python@rcn.com>
parents: 34898
diff changeset
788 returns an empty list.
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
789 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
790
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
791 \begin{methoddesc}[string]{splitlines}{\optional{keepends}}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
792 Return a list of the lines in the string, breaking at line
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
793 boundaries. Line breaks are not included in the resulting list unless
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
794 \var{keepends} is given and true.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
795 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
796
23017
44637bd7f59b Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
parents: 22994
diff changeset
797 \begin{methoddesc}[string]{startswith}{prefix\optional{,
44637bd7f59b Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
parents: 22994
diff changeset
798 start\optional{, end}}}
28171
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
799 Return \code{True} if string starts with the \var{prefix}, otherwise
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
800 return \code{False}. With optional \var{start}, test string beginning at
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
801 that position. With optional \var{end}, stop comparing string at that
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
802 position.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
803 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
804
23017
44637bd7f59b Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
parents: 22994
diff changeset
805 \begin{methoddesc}[string]{strip}{\optional{chars}}
34975
5e511ddef48b SF bug #1202395: Description of string.lstrip() needs improvement
Raymond Hettinger <python@rcn.com>
parents: 34969
diff changeset
806 Return a copy of the string with the leading and trailing characters
5e511ddef48b SF bug #1202395: Description of string.lstrip() needs improvement
Raymond Hettinger <python@rcn.com>
parents: 34969
diff changeset
807 removed. The \var{chars} argument is a string specifying the set of
5e511ddef48b SF bug #1202395: Description of string.lstrip() needs improvement
Raymond Hettinger <python@rcn.com>
parents: 34969
diff changeset
808 characters to be removed. If omitted or \code{None}, the \var{chars}
5e511ddef48b SF bug #1202395: Description of string.lstrip() needs improvement
Raymond Hettinger <python@rcn.com>
parents: 34969
diff changeset
809 argument defaults to removing whitespace. The \var{chars} argument is not
5e511ddef48b SF bug #1202395: Description of string.lstrip() needs improvement
Raymond Hettinger <python@rcn.com>
parents: 34969
diff changeset
810 a prefix or suffix; rather, all combinations of its values are stripped:
5e511ddef48b SF bug #1202395: Description of string.lstrip() needs improvement
Raymond Hettinger <python@rcn.com>
parents: 34969
diff changeset
811 \begin{verbatim}
5e511ddef48b SF bug #1202395: Description of string.lstrip() needs improvement
Raymond Hettinger <python@rcn.com>
parents: 34969
diff changeset
812 >>> ' spacious '.strip()
5e511ddef48b SF bug #1202395: Description of string.lstrip() needs improvement
Raymond Hettinger <python@rcn.com>
parents: 34969
diff changeset
813 'spacious'
5e511ddef48b SF bug #1202395: Description of string.lstrip() needs improvement
Raymond Hettinger <python@rcn.com>
parents: 34969
diff changeset
814 >>> 'www.example.com'.strip('cmowz.')
5e511ddef48b SF bug #1202395: Description of string.lstrip() needs improvement
Raymond Hettinger <python@rcn.com>
parents: 34969
diff changeset
815 'example'
5e511ddef48b SF bug #1202395: Description of string.lstrip() needs improvement
Raymond Hettinger <python@rcn.com>
parents: 34969
diff changeset
816 \end{verbatim}
26259
60d809a25bae Document that a minor feature was added in 2.2.2. ;-(
Fred Drake <fdrake@acm.org>
parents: 26161
diff changeset
817 \versionchanged[Support for the \var{chars} argument]{2.2.2}
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
818 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
819
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
820 \begin{methoddesc}[string]{swapcase}{}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
821 Return a copy of the string with uppercase characters converted to
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
822 lowercase and vice versa.
32214
6478eb6ae3c0 Document string methods that are locale-dependent. Fixes #935749.
Martin v. Löwis <martin@v.loewis.de>
parents: 32197
diff changeset
823
6478eb6ae3c0 Document string methods that are locale-dependent. Fixes #935749.
Martin v. Löwis <martin@v.loewis.de>
parents: 32197
diff changeset
824 For 8-bit strings, this method is locale-dependent.
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
825 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
826
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
827 \begin{methoddesc}[string]{title}{}
18416
33b4357aebb8 Fix up a few style nits -- avoid "e.g." and "i.e." -- these make
Fred Drake <fdrake@acm.org>
parents: 18395
diff changeset
828 Return a titlecased version of the string: words start with uppercase
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
829 characters, all remaining cased characters are lowercase.
32214
6478eb6ae3c0 Document string methods that are locale-dependent. Fixes #935749.
Martin v. Löwis <martin@v.loewis.de>
parents: 32197
diff changeset
830
6478eb6ae3c0 Document string methods that are locale-dependent. Fixes #935749.
Martin v. Löwis <martin@v.loewis.de>
parents: 32197
diff changeset
831 For 8-bit strings, this method is locale-dependent.
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
832 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
833
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
834 \begin{methoddesc}[string]{translate}{table\optional{, deletechars}}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
835 Return a copy of the string where all characters occurring in the
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
836 optional argument \var{deletechars} are removed, and the remaining
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
837 characters have been mapped through the given translation table, which
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
838 must be a string of length 256.
29893
e9dddfd2a62f Discussion of signatures for unicode.translate() and str.translate()
Raymond Hettinger <python@rcn.com>
parents: 29590
diff changeset
839
e9dddfd2a62f Discussion of signatures for unicode.translate() and str.translate()
Raymond Hettinger <python@rcn.com>
parents: 29590
diff changeset
840 For Unicode objects, the \method{translate()} method does not
e9dddfd2a62f Discussion of signatures for unicode.translate() and str.translate()
Raymond Hettinger <python@rcn.com>
parents: 29590
diff changeset
841 accept the optional \var{deletechars} argument. Instead, it
e9dddfd2a62f Discussion of signatures for unicode.translate() and str.translate()
Raymond Hettinger <python@rcn.com>
parents: 29590
diff changeset
842 returns a copy of the \var{s} where all characters have been mapped
e9dddfd2a62f Discussion of signatures for unicode.translate() and str.translate()
Raymond Hettinger <python@rcn.com>
parents: 29590
diff changeset
843 through the given translation table which must be a mapping of
e9dddfd2a62f Discussion of signatures for unicode.translate() and str.translate()
Raymond Hettinger <python@rcn.com>
parents: 29590
diff changeset
844 Unicode ordinals to Unicode ordinals, Unicode strings or \code{None}.
e9dddfd2a62f Discussion of signatures for unicode.translate() and str.translate()
Raymond Hettinger <python@rcn.com>
parents: 29590
diff changeset
845 Unmapped characters are left untouched. Characters mapped to \code{None}
e9dddfd2a62f Discussion of signatures for unicode.translate() and str.translate()
Raymond Hettinger <python@rcn.com>
parents: 29590
diff changeset
846 are deleted. Note, a more flexible approach is to create a custom
e9dddfd2a62f Discussion of signatures for unicode.translate() and str.translate()
Raymond Hettinger <python@rcn.com>
parents: 29590
diff changeset
847 character mapping codec using the \refmodule{codecs} module (see
e9dddfd2a62f Discussion of signatures for unicode.translate() and str.translate()
Raymond Hettinger <python@rcn.com>
parents: 29590
diff changeset
848 \module{encodings.cp1251} for an example).
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
849 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
850
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
851 \begin{methoddesc}[string]{upper}{}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
852 Return a copy of the string converted to uppercase.
32214
6478eb6ae3c0 Document string methods that are locale-dependent. Fixes #935749.
Martin v. Löwis <martin@v.loewis.de>
parents: 32197
diff changeset
853
6478eb6ae3c0 Document string methods that are locale-dependent. Fixes #935749.
Martin v. Löwis <martin@v.loewis.de>
parents: 32197
diff changeset
854 For 8-bit strings, this method is locale-dependent.
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
855 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
856
23045
8b1268bc371a Apply the second version of SF patch http://www.python.org/sf/536241
Walter Dörwald <walter@livinglogic.de>
parents: 23017
diff changeset
857 \begin{methoddesc}[string]{zfill}{width}
8b1268bc371a Apply the second version of SF patch http://www.python.org/sf/536241
Walter Dörwald <walter@livinglogic.de>
parents: 23017
diff changeset
858 Return the numeric string left filled with zeros in a string
8b1268bc371a Apply the second version of SF patch http://www.python.org/sf/536241
Walter Dörwald <walter@livinglogic.de>
parents: 23017
diff changeset
859 of length \var{width}. The original string is returned if
8b1268bc371a Apply the second version of SF patch http://www.python.org/sf/536241
Walter Dörwald <walter@livinglogic.de>
parents: 23017
diff changeset
860 \var{width} is less than \code{len(\var{s})}.
26260
b327ffcfe9b7 Better note that str.zfill() was added in 2.2.2 as well. ;-(
Fred Drake <fdrake@acm.org>
parents: 26259
diff changeset
861 \versionadded{2.2.2}
23045
8b1268bc371a Apply the second version of SF patch http://www.python.org/sf/536241
Walter Dörwald <walter@livinglogic.de>
parents: 23017
diff changeset
862 \end{methoddesc}
8b1268bc371a Apply the second version of SF patch http://www.python.org/sf/536241
Walter Dörwald <walter@livinglogic.de>
parents: 23017
diff changeset
863
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
864
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
865 \subsubsection{String Formatting Operations \label{typesseq-strings}}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
866
21177
7d1eac41ce3e Slightly improved indexing for the string-% operator, thanks to comments
Fred Drake <fdrake@acm.org>
parents: 21163
diff changeset
867 \index{formatting, string (\%{})}
21542
5d4135609efc Added index entries similar to some recommended by Skip, and used the word
Fred Drake <fdrake@acm.org>
parents: 21332
diff changeset
868 \index{interpolation, string (\%{})}
14552
a8d1c030b19f Add some index entries to make it easier to find information on
Fred Drake <fdrake@acm.org>
parents: 14520
diff changeset
869 \index{string!formatting}
21542
5d4135609efc Added index entries similar to some recommended by Skip, and used the word
Fred Drake <fdrake@acm.org>
parents: 21332
diff changeset
870 \index{string!interpolation}
14552
a8d1c030b19f Add some index entries to make it easier to find information on
Fred Drake <fdrake@acm.org>
parents: 14520
diff changeset
871 \index{printf-style formatting}
a8d1c030b19f Add some index entries to make it easier to find information on
Fred Drake <fdrake@acm.org>
parents: 14520
diff changeset
872 \index{sprintf-style formatting}
21177
7d1eac41ce3e Slightly improved indexing for the string-% operator, thanks to comments
Fred Drake <fdrake@acm.org>
parents: 21163
diff changeset
873 \index{\protect\%{} formatting}
21542
5d4135609efc Added index entries similar to some recommended by Skip, and used the word
Fred Drake <fdrake@acm.org>
parents: 21332
diff changeset
874 \index{\protect\%{} interpolation}
14552
a8d1c030b19f Add some index entries to make it easier to find information on
Fred Drake <fdrake@acm.org>
parents: 14520
diff changeset
875
16285
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
876 String and Unicode objects have one unique built-in operation: the
21542
5d4135609efc Added index entries similar to some recommended by Skip, and used the word
Fred Drake <fdrake@acm.org>
parents: 21332
diff changeset
877 \code{\%} operator (modulo). This is also known as the string
5d4135609efc Added index entries similar to some recommended by Skip, and used the word
Fred Drake <fdrake@acm.org>
parents: 21332
diff changeset
878 \emph{formatting} or \emph{interpolation} operator. Given
5d4135609efc Added index entries similar to some recommended by Skip, and used the word
Fred Drake <fdrake@acm.org>
parents: 21332
diff changeset
879 \code{\var{format} \% \var{values}} (where \var{format} is a string or
5d4135609efc Added index entries similar to some recommended by Skip, and used the word
Fred Drake <fdrake@acm.org>
parents: 21332
diff changeset
880 Unicode object), \code{\%} conversion specifications in \var{format}
5d4135609efc Added index entries similar to some recommended by Skip, and used the word
Fred Drake <fdrake@acm.org>
parents: 21332
diff changeset
881 are replaced with zero or more elements of \var{values}. The effect
5d4135609efc Added index entries similar to some recommended by Skip, and used the word
Fred Drake <fdrake@acm.org>
parents: 21332
diff changeset
882 is similar to the using \cfunction{sprintf()} in the C language. If
5d4135609efc Added index entries similar to some recommended by Skip, and used the word
Fred Drake <fdrake@acm.org>
parents: 21332
diff changeset
883 \var{format} is a Unicode object, or if any of the objects being
5d4135609efc Added index entries similar to some recommended by Skip, and used the word
Fred Drake <fdrake@acm.org>
parents: 21332
diff changeset
884 converted using the \code{\%s} conversion are Unicode objects, the
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
885 result will also be a Unicode object.
16285
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
886
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
887 If \var{format} requires a single argument, \var{values} may be a
31286
3894654b4848 fix a variety of markup bugs
Fred Drake <fdrake@acm.org>
parents: 31282
diff changeset
888 single non-tuple object.\footnote{To format only a tuple you
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
889 should therefore provide a singleton tuple whose only element
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
890 is the tuple to be formatted.} Otherwise, \var{values} must be a tuple with
16285
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
891 exactly the number of items specified by the format string, or a
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
892 single mapping object (for example, a dictionary).
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
893
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
894 A conversion specifier contains two or more characters and has the
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
895 following components, which must occur in this order:
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
896
16285
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
897 \begin{enumerate}
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
898 \item The \character{\%} character, which marks the start of the
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
899 specifier.
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
900 \item Mapping key (optional), consisting of a parenthesised sequence
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
901 of characters (for example, \code{(somename)}).
16285
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
902 \item Conversion flags (optional), which affect the result of some
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
903 conversion types.
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
904 \item Minimum field width (optional). If specified as an
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
905 \character{*} (asterisk), the actual width is read from the
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
906 next element of the tuple in \var{values}, and the object to
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
907 convert comes after the minimum field width and optional
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
908 precision.
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
909 \item Precision (optional), given as a \character{.} (dot) followed
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
910 by the precision. If specified as \character{*} (an
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
911 asterisk), the actual width is read from the next element of
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
912 the tuple in \var{values}, and the value to convert comes after
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
913 the precision.
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
914 \item Length modifier (optional).
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
915 \item Conversion type.
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
916 \end{enumerate}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
917
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
918 When the right argument is a dictionary (or other mapping type), then
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
919 the formats in the string \emph{must} include a parenthesised mapping key into
16285
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
920 that dictionary inserted immediately after the \character{\%}
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
921 character. The mapping key selects the value to be formatted from the
16285
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
922 mapping. For example:
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
923
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
924 \begin{verbatim}
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
925 >>> print '%(language)s has %(#)03d quote types.' % \
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
926 {'language': "Python", "#": 2}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
927 Python has 002 quote types.
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
928 \end{verbatim}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
929
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
930 In this case no \code{*} specifiers may occur in a format (since they
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
931 require a sequential parameter list).
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
932
16285
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
933 The conversion flag characters are:
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
934
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
935 \begin{tableii}{c|l}{character}{Flag}{Meaning}
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
936 \lineii{\#}{The value conversion will use the ``alternate form''
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
937 (where defined below).}
27919
4b5c2e025c5e Fix SF bug #687655, String formatting conversions misleading
Neal Norwitz <nnorwitz@gmail.com>
parents: 27225
diff changeset
938 \lineii{0}{The conversion will be zero padded for numeric values.}
16285
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
939 \lineii{-}{The converted value is left adjusted (overrides
25906
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
940 the \character{0} conversion if both are given).}
16285
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
941 \lineii{{~}}{(a space) A blank should be left before a positive number
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
942 (or empty string) produced by a signed conversion.}
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
943 \lineii{+}{A sign character (\character{+} or \character{-}) will
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
944 precede the conversion (overrides a "space" flag).}
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
945 \end{tableii}
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
946
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
947 The length modifier may be \code{h}, \code{l}, and \code{L} may be
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
948 present, but are ignored as they are not necessary for Python.
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
949
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
950 The conversion types are:
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
951
25906
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
952 \begin{tableiii}{c|l|c}{character}{Conversion}{Meaning}{Notes}
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
953 \lineiii{d}{Signed integer decimal.}{}
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
954 \lineiii{i}{Signed integer decimal.}{}
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
955 \lineiii{o}{Unsigned octal.}{(1)}
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
956 \lineiii{u}{Unsigned decimal.}{}
34296
67f2190e1f6d SF Patch #1093896: miscellaneous doc typos
Raymond Hettinger <python@rcn.com>
parents: 34078
diff changeset
957 \lineiii{x}{Unsigned hexadecimal (lowercase).}{(2)}
67f2190e1f6d SF Patch #1093896: miscellaneous doc typos
Raymond Hettinger <python@rcn.com>
parents: 34078
diff changeset
958 \lineiii{X}{Unsigned hexadecimal (uppercase).}{(2)}
25906
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
959 \lineiii{e}{Floating point exponential format (lowercase).}{}
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
960 \lineiii{E}{Floating point exponential format (uppercase).}{}
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
961 \lineiii{f}{Floating point decimal format.}{}
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
962 \lineiii{F}{Floating point decimal format.}{}
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
963 \lineiii{g}{Same as \character{e} if exponent is greater than -4 or
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
964 less than precision, \character{f} otherwise.}{}
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
965 \lineiii{G}{Same as \character{E} if exponent is greater than -4 or
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
966 less than precision, \character{F} otherwise.}{}
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
967 \lineiii{c}{Single character (accepts integer or single character
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
968 string).}{}
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
969 \lineiii{r}{String (converts any python object using
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
970 \function{repr()}).}{(3)}
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
971 \lineiii{s}{String (converts any python object using
27225
5d42dba49fe5 SF patch 664183 and SF bug 664044: Note that both u'%s' % 'x' and
Raymond Hettinger <python@rcn.com>
parents: 27036
diff changeset
972 \function{str()}).}{(4)}
25906
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
973 \lineiii{\%}{No argument is converted, results in a \character{\%}
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
974 character in the result.}{}
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
975 \end{tableiii}
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
976
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
977 \noindent
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
978 Notes:
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
979 \begin{description}
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
980 \item[(1)]
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
981 The alternate form causes a leading zero (\character{0}) to be
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
982 inserted between left-hand padding and the formatting of the
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
983 number if the leading character of the result is not already a
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
984 zero.
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
985 \item[(2)]
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
986 The alternate form causes a leading \code{'0x'} or \code{'0X'}
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
987 (depending on whether the \character{x} or \character{X} format
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
988 was used) to be inserted between left-hand padding and the
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
989 formatting of the number if the leading character of the result is
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
990 not already a zero.
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
991 \item[(3)]
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
992 The \code{\%r} conversion was added in Python 2.0.
27225
5d42dba49fe5 SF patch 664183 and SF bug 664044: Note that both u'%s' % 'x' and
Raymond Hettinger <python@rcn.com>
parents: 27036
diff changeset
993 \item[(4)]
5d42dba49fe5 SF patch 664183 and SF bug 664044: Note that both u'%s' % 'x' and
Raymond Hettinger <python@rcn.com>
parents: 27036
diff changeset
994 If the object or format provided is a \class{unicode} string,
5d42dba49fe5 SF patch 664183 and SF bug 664044: Note that both u'%s' % 'x' and
Raymond Hettinger <python@rcn.com>
parents: 27036
diff changeset
995 the resulting string will also be \class{unicode}.
25906
50905db35da5 - The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
parents: 25393
diff changeset
996 \end{description}
16285
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
997
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
998 % XXX Examples?
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
999
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
1000 Since Python strings have an explicit length, \code{\%s} conversions
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
1001 do not assume that \code{'\e0'} is the end of the string.
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
1002
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
1003 For safety reasons, floating point precisions are clipped to 50;
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
1004 \code{\%f} conversions for numbers whose absolute value is over 1e25
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
1005 are replaced by \code{\%g} conversions.\footnote{
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
1006 These numbers are fairly arbitrary. They are intended to
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
1007 avoid printing endless strings of meaningless digits without hampering
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
1008 correct use and without having to know the exact precision of floating
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
1009 point values on a particular machine.
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
1010 } All other errors raise exceptions.
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
1011
21163
7b6879714b74 Make no assumption about how modules are built when referring to them; this
Fred Drake <fdrake@acm.org>
parents: 21159
diff changeset
1012 Additional string operations are defined in standard modules
31286
3894654b4848 fix a variety of markup bugs
Fred Drake <fdrake@acm.org>
parents: 31282
diff changeset
1013 \refmodule{string}\refstmodindex{string}\ and
22241
7584b6f1afde Change Windows file.truncate() to (a) restore the original file position,
Tim Peters <tim.peters@gmail.com>
parents: 22214
diff changeset
1014 \refmodule{re}.\refstmodindex{re}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1015
13967
7b7ee58901fb Document the range type, as suggested by Denis S. Otkidach
Fred Drake <fdrake@acm.org>
parents: 13933
diff changeset
1016
14044
a905c5aa0691 As pointed out by Denis S. Otkidach <den@analyt.chem.msu.ru>, xrange()
Fred Drake <fdrake@acm.org>
parents: 13967
diff changeset
1017 \subsubsection{XRange Type \label{typesseq-xrange}}
13967
7b7ee58901fb Document the range type, as suggested by Denis S. Otkidach
Fred Drake <fdrake@acm.org>
parents: 13933
diff changeset
1018
31286
3894654b4848 fix a variety of markup bugs
Fred Drake <fdrake@acm.org>
parents: 31282
diff changeset
1019 The \class{xrange}\obindex{xrange} type is an immutable sequence which
3894654b4848 fix a variety of markup bugs
Fred Drake <fdrake@acm.org>
parents: 31282
diff changeset
1020 is commonly used for looping. The advantage of the \class{xrange}
3894654b4848 fix a variety of markup bugs
Fred Drake <fdrake@acm.org>
parents: 31282
diff changeset
1021 type is that an \class{xrange} object will always take the same amount
3894654b4848 fix a variety of markup bugs
Fred Drake <fdrake@acm.org>
parents: 31282
diff changeset
1022 of memory, no matter the size of the range it represents. There are
3894654b4848 fix a variety of markup bugs
Fred Drake <fdrake@acm.org>
parents: 31282
diff changeset
1023 no consistent performance advantages.
13967
7b7ee58901fb Document the range type, as suggested by Denis S. Otkidach
Fred Drake <fdrake@acm.org>
parents: 13933
diff changeset
1024
26592
0c646baeec58 Update comments about the performance of xrange().
Raymond Hettinger <python@rcn.com>
parents: 26514
diff changeset
1025 XRange objects have very little behavior: they only support indexing,
0c646baeec58 Update comments about the performance of xrange().
Raymond Hettinger <python@rcn.com>
parents: 26514
diff changeset
1026 iteration, and the \function{len()} function.
13967
7b7ee58901fb Document the range type, as suggested by Denis S. Otkidach
Fred Drake <fdrake@acm.org>
parents: 13933
diff changeset
1027
7b7ee58901fb Document the range type, as suggested by Denis S. Otkidach
Fred Drake <fdrake@acm.org>
parents: 13933
diff changeset
1028
10156
0f7d694bc334 Make sure all HTML pages generated from this section have reasonable
Fred Drake <fdrake@acm.org>
parents: 10147
diff changeset
1029 \subsubsection{Mutable Sequence Types \label{typesseq-mutable}}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1030
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1031 List objects support additional operations that allow in-place
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1032 modification of the object.
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
1033 Other mutable sequence types (when added to the language) should
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
1034 also support these operations.
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
1035 Strings and tuples are immutable sequence types: such objects cannot
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1036 be modified once created.
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1037 The following operations are defined on mutable sequence types (where
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1038 \var{x} is an arbitrary object):
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1039 \indexiii{mutable}{sequence}{types}
15005
0cf5111bf09c Use \obindex{...} instead of \indexii{...}{type} in many places; this is
Fred Drake <fdrake@acm.org>
parents: 14710
diff changeset
1040 \obindex{list}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1041
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1042 \begin{tableiii}{c|l|c}{code}{Operation}{Result}{Notes}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1043 \lineiii{\var{s}[\var{i}] = \var{x}}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1044 {item \var{i} of \var{s} is replaced by \var{x}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1045 \lineiii{\var{s}[\var{i}:\var{j}] = \var{t}}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1046 {slice of \var{s} from \var{i} to \var{j} is replaced by \var{t}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1047 \lineiii{del \var{s}[\var{i}:\var{j}]}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1048 {same as \code{\var{s}[\var{i}:\var{j}] = []}}{}
28171
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Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1049 \lineiii{\var{s}[\var{i}:\var{j}:\var{k}] = \var{t}}
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1050 {the elements of \code{\var{s}[\var{i}:\var{j}:\var{k}]} are replaced by those of \var{t}}{(1)}
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1051 \lineiii{del \var{s}[\var{i}:\var{j}:\var{k}]}
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1052 {removes the elements of \code{\var{s}[\var{i}:\var{j}:\var{k}]} from the list}{}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1053 \lineiii{\var{s}.append(\var{x})}
28171
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1054 {same as \code{\var{s}[len(\var{s}):len(\var{s})] = [\var{x}]}}{(2)}
9318
8a26e55e18b8 Document the new list.extend() method. Interesting enough, the
Barry Warsaw <barry@python.org>
parents: 9083
diff changeset
1055 \lineiii{\var{s}.extend(\var{x})}
28171
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1056 {same as \code{\var{s}[len(\var{s}):len(\var{s})] = \var{x}}}{(3)}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1057 \lineiii{\var{s}.count(\var{x})}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1058 {return number of \var{i}'s for which \code{\var{s}[\var{i}] == \var{x}}}{}
29516
d761ff55b3be Updated documentation for the new slice arguments for list.index().
Walter Dörwald <walter@livinglogic.de>
parents: 29343
diff changeset
1059 \lineiii{\var{s}.index(\var{x}\optional{, \var{i}\optional{, \var{j}}})}
d761ff55b3be Updated documentation for the new slice arguments for list.index().
Walter Dörwald <walter@livinglogic.de>
parents: 29343
diff changeset
1060 {return smallest \var{k} such that \code{\var{s}[\var{k}] == \var{x}} and
d761ff55b3be Updated documentation for the new slice arguments for list.index().
Walter Dörwald <walter@livinglogic.de>
parents: 29343
diff changeset
1061 \code{\var{i} <= \var{k} < \var{j}}}{(4)}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1062 \lineiii{\var{s}.insert(\var{i}, \var{x})}
28606
436d812f2b94 - list.insert(i, x) now interprets negative i as it would be
Guido van Rossum <guido@python.org>
parents: 28337
diff changeset
1063 {same as \code{\var{s}[\var{i}:\var{i}] = [\var{x}]}}{(5)}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1064 \lineiii{\var{s}.pop(\optional{\var{i}})}
28171
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1065 {same as \code{\var{x} = \var{s}[\var{i}]; del \var{s}[\var{i}]; return \var{x}}}{(6)}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1066 \lineiii{\var{s}.remove(\var{x})}
28171
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1067 {same as \code{del \var{s}[\var{s}.index(\var{x})]}}{(4)}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1068 \lineiii{\var{s}.reverse()}
28171
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1069 {reverses the items of \var{s} in place}{(7)}
31286
3894654b4848 fix a variety of markup bugs
Fred Drake <fdrake@acm.org>
parents: 31282
diff changeset
1070 \lineiii{\var{s}.sort(\optional{\var{cmp}\optional{,
3894654b4848 fix a variety of markup bugs
Fred Drake <fdrake@acm.org>
parents: 31282
diff changeset
1071 \var{key}\optional{, \var{reverse}}}})}
28171
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1072 {sort the items of \var{s} in place}{(7), (8), (9), (10)}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1073 \end{tableiii}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1074 \indexiv{operations on}{mutable}{sequence}{types}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1075 \indexiii{operations on}{sequence}{types}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1076 \indexiii{operations on}{list}{type}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1077 \indexii{subscript}{assignment}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1078 \indexii{slice}{assignment}
28171
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1079 \indexii{extended slice}{assignment}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1080 \stindex{del}
10156
0f7d694bc334 Make sure all HTML pages generated from this section have reasonable
Fred Drake <fdrake@acm.org>
parents: 10147
diff changeset
1081 \withsubitem{(list method)}{
11183
1e0b1967be7f In note mentioning [].remove()'s exception, tell what exception is
Fred Drake <fdrake@acm.org>
parents: 11100
diff changeset
1082 \ttindex{append()}\ttindex{extend()}\ttindex{count()}\ttindex{index()}
1e0b1967be7f In note mentioning [].remove()'s exception, tell what exception is
Fred Drake <fdrake@acm.org>
parents: 11100
diff changeset
1083 \ttindex{insert()}\ttindex{pop()}\ttindex{remove()}\ttindex{reverse()}
9523
ed6cacddc6c6 Fix indexing of func_code attribute; this is on a function, not a code
Fred Drake <fdrake@acm.org>
parents: 9461
diff changeset
1084 \ttindex{sort()}}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1085 \noindent
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1086 Notes:
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1087 \begin{description}
28171
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1088 \item[(1)] \var{t} must have the same length as the slice it is
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1089 replacing.
23778
245224d1b8c9 This is my nearly two year old patch
Michael W. Hudson <mwh@python.net>
parents: 23515
diff changeset
1090
28171
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1091 \item[(2)] The C implementation of Python has historically accepted
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1092 multiple parameters and implicitly joined them into a tuple; this
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1093 no longer works in Python 2.0. Use of this misfeature has been
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1094 deprecated since Python 1.4.
12223
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
1095
34573
19327db75d1c SF bug #1119700: list extend() accepts args besides lists
Raymond Hettinger <python@rcn.com>
parents: 34508
diff changeset
1096 \item[(3)] \var{x} can be any iterable object.
28171
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1097
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1098 \item[(4)] Raises \exception{ValueError} when \var{x} is not found in
29516
d761ff55b3be Updated documentation for the new slice arguments for list.index().
Walter Dörwald <walter@livinglogic.de>
parents: 29343
diff changeset
1099 \var{s}. When a negative index is passed as the second or third parameter
d761ff55b3be Updated documentation for the new slice arguments for list.index().
Walter Dörwald <walter@livinglogic.de>
parents: 29343
diff changeset
1100 to the \method{index()} method, the list length is added, as for slice
d761ff55b3be Updated documentation for the new slice arguments for list.index().
Walter Dörwald <walter@livinglogic.de>
parents: 29343
diff changeset
1101 indices. If it is still negative, it is truncated to zero, as for
d761ff55b3be Updated documentation for the new slice arguments for list.index().
Walter Dörwald <walter@livinglogic.de>
parents: 29343
diff changeset
1102 slice indices. \versionchanged[Previously, \method{index()} didn't
d761ff55b3be Updated documentation for the new slice arguments for list.index().
Walter Dörwald <walter@livinglogic.de>
parents: 29343
diff changeset
1103 have arguments for specifying start and stop positions]{2.3}
11183
1e0b1967be7f In note mentioning [].remove()'s exception, tell what exception is
Fred Drake <fdrake@acm.org>
parents: 11100
diff changeset
1104
28171
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1105 \item[(5)] When a negative index is passed as the first parameter to
28606
436d812f2b94 - list.insert(i, x) now interprets negative i as it would be
Guido van Rossum <guido@python.org>
parents: 28337
diff changeset
1106 the \method{insert()} method, the list length is added, as for slice
436d812f2b94 - list.insert(i, x) now interprets negative i as it would be
Guido van Rossum <guido@python.org>
parents: 28337
diff changeset
1107 indices. If it is still negative, it is truncated to zero, as for
436d812f2b94 - list.insert(i, x) now interprets negative i as it would be
Guido van Rossum <guido@python.org>
parents: 28337
diff changeset
1108 slice indices. \versionchanged[Previously, all negative indices
436d812f2b94 - list.insert(i, x) now interprets negative i as it would be
Guido van Rossum <guido@python.org>
parents: 28337
diff changeset
1109 were truncated to zero]{2.3}
20701
5f6850d1f9e8 Explain what [].insert() does when the target index is negative.
Fred Drake <fdrake@acm.org>
parents: 20580
diff changeset
1110
28171
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1111 \item[(6)] The \method{pop()} method is only supported by the list and
13777
b3903e05017f Stop lying about [].pop() being experimental! There is no backing it out
Fred Drake <fdrake@acm.org>
parents: 13772
diff changeset
1112 array types. The optional argument \var{i} defaults to \code{-1},
b3903e05017f Stop lying about [].pop() being experimental! There is no backing it out
Fred Drake <fdrake@acm.org>
parents: 13772
diff changeset
1113 so that by default the last item is removed and returned.
12223
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
1114
28171
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1115 \item[(7)] The \method{sort()} and \method{reverse()} methods modify the
12223
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
1116 list in place for economy of space when sorting or reversing a large
18829
1bc1fdf1482b trivial rewording in footnote 5.
Skip Montanaro <skip@pobox.com>
parents: 18416
diff changeset
1117 list. To remind you that they operate by side effect, they don't return
1bc1fdf1482b trivial rewording in footnote 5.
Skip Montanaro <skip@pobox.com>
parents: 18416
diff changeset
1118 the sorted or reversed list.
12223
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
1119
31210
c06b570adf12 Guido grants a Christmas wish:
Raymond Hettinger <python@rcn.com>
parents: 31206
diff changeset
1120 \item[(8)] The \method{sort()} method takes optional arguments for
33448
5570fae1f01c Typo fix: 'comparisions' is not a word
Andrew M. Kuchling <amk@amk.ca>
parents: 33412
diff changeset
1121 controlling the comparisons.
30697
1345c23a0591 * list.sort() now supports three keyword arguments: cmp, key, and reverse.
Raymond Hettinger <python@rcn.com>
parents: 30413
diff changeset
1122
1345c23a0591 * list.sort() now supports three keyword arguments: cmp, key, and reverse.
Raymond Hettinger <python@rcn.com>
parents: 30413
diff changeset
1123 \var{cmp} specifies a custom comparison function of two arguments
1345c23a0591 * list.sort() now supports three keyword arguments: cmp, key, and reverse.
Raymond Hettinger <python@rcn.com>
parents: 30413
diff changeset
1124 (list items) which should return a negative, zero or positive number
1345c23a0591 * list.sort() now supports three keyword arguments: cmp, key, and reverse.
Raymond Hettinger <python@rcn.com>
parents: 30413
diff changeset
1125 depending on whether the first argument is considered smaller than,
1345c23a0591 * list.sort() now supports three keyword arguments: cmp, key, and reverse.
Raymond Hettinger <python@rcn.com>
parents: 30413
diff changeset
1126 equal to, or larger than the second argument:
1345c23a0591 * list.sort() now supports three keyword arguments: cmp, key, and reverse.
Raymond Hettinger <python@rcn.com>
parents: 30413
diff changeset
1127 \samp{\var{cmp}=\keyword{lambda} \var{x},\var{y}:
1345c23a0591 * list.sort() now supports three keyword arguments: cmp, key, and reverse.
Raymond Hettinger <python@rcn.com>
parents: 30413
diff changeset
1128 \function{cmp}(x.lower(), y.lower())}
1345c23a0591 * list.sort() now supports three keyword arguments: cmp, key, and reverse.
Raymond Hettinger <python@rcn.com>
parents: 30413
diff changeset
1129
1345c23a0591 * list.sort() now supports three keyword arguments: cmp, key, and reverse.
Raymond Hettinger <python@rcn.com>
parents: 30413
diff changeset
1130 \var{key} specifies a function of one argument that is used to
1345c23a0591 * list.sort() now supports three keyword arguments: cmp, key, and reverse.
Raymond Hettinger <python@rcn.com>
parents: 30413
diff changeset
1131 extract a comparison key from each list element:
34078
4b601bd346a4 Backport minor documentation fixups.
Raymond Hettinger <python@rcn.com>
parents: 34029
diff changeset
1132 \samp{\var{key}=\function{str.lower}}
30697
1345c23a0591 * list.sort() now supports three keyword arguments: cmp, key, and reverse.
Raymond Hettinger <python@rcn.com>
parents: 30413
diff changeset
1133
1345c23a0591 * list.sort() now supports three keyword arguments: cmp, key, and reverse.
Raymond Hettinger <python@rcn.com>
parents: 30413
diff changeset
1134 \var{reverse} is a boolean value. If set to \code{True}, then the
1345c23a0591 * list.sort() now supports three keyword arguments: cmp, key, and reverse.
Raymond Hettinger <python@rcn.com>
parents: 30413
diff changeset
1135 list elements are sorted as if each comparison were reversed.
1345c23a0591 * list.sort() now supports three keyword arguments: cmp, key, and reverse.
Raymond Hettinger <python@rcn.com>
parents: 30413
diff changeset
1136
1345c23a0591 * list.sort() now supports three keyword arguments: cmp, key, and reverse.
Raymond Hettinger <python@rcn.com>
parents: 30413
diff changeset
1137 In general, the \var{key} and \var{reverse} conversion processes are
1345c23a0591 * list.sort() now supports three keyword arguments: cmp, key, and reverse.
Raymond Hettinger <python@rcn.com>
parents: 30413
diff changeset
1138 much faster than specifying an equivalent \var{cmp} function. This is
1345c23a0591 * list.sort() now supports three keyword arguments: cmp, key, and reverse.
Raymond Hettinger <python@rcn.com>
parents: 30413
diff changeset
1139 because \var{cmp} is called multiple times for each list element while
30737
38b0b7d41936 markup fixes; this would not format
Fred Drake <fdrake@acm.org>
parents: 30707
diff changeset
1140 \var{key} and \var{reverse} touch each element only once.
30697
1345c23a0591 * list.sort() now supports three keyword arguments: cmp, key, and reverse.
Raymond Hettinger <python@rcn.com>
parents: 30413
diff changeset
1141
28337
90f17c374f59 - added example of using a comparison function with list.sort(), and
Fred Drake <fdrake@acm.org>
parents: 28211
diff changeset
1142 \versionchanged[Support for \code{None} as an equivalent to omitting
31286
3894654b4848 fix a variety of markup bugs
Fred Drake <fdrake@acm.org>
parents: 31282
diff changeset
1143 \var{cmp} was added]{2.3}
28337
90f17c374f59 - added example of using a comparison function with list.sort(), and
Fred Drake <fdrake@acm.org>
parents: 28211
diff changeset
1144
30737
38b0b7d41936 markup fixes; this would not format
Fred Drake <fdrake@acm.org>
parents: 30707
diff changeset
1145 \versionchanged[Support for \var{key} and \var{reverse} was added]{2.4}
28337
90f17c374f59 - added example of using a comparison function with list.sort(), and
Fred Drake <fdrake@acm.org>
parents: 28211
diff changeset
1146
31286
3894654b4848 fix a variety of markup bugs
Fred Drake <fdrake@acm.org>
parents: 31282
diff changeset
1147 \item[(9)] Starting with Python 2.3, the \method{sort()} method is
31210
c06b570adf12 Guido grants a Christmas wish:
Raymond Hettinger <python@rcn.com>
parents: 31206
diff changeset
1148 guaranteed to be stable. A sort is stable if it guarantees not to
30697
1345c23a0591 * list.sort() now supports three keyword arguments: cmp, key, and reverse.
Raymond Hettinger <python@rcn.com>
parents: 30413
diff changeset
1149 change the relative order of elements that compare equal --- this is
1345c23a0591 * list.sort() now supports three keyword arguments: cmp, key, and reverse.
Raymond Hettinger <python@rcn.com>
parents: 30413
diff changeset
1150 helpful for sorting in multiple passes (for example, sort by
1345c23a0591 * list.sort() now supports three keyword arguments: cmp, key, and reverse.
Raymond Hettinger <python@rcn.com>
parents: 30413
diff changeset
1151 department, then by salary grade).
26161
dd10d97d329a SF patch 637176: list.sort crasher
Tim Peters <tim.peters@gmail.com>
parents: 25906
diff changeset
1152
28171
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Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1153 \item[(10)] While a list is being sorted, the effect of attempting to
31286
3894654b4848 fix a variety of markup bugs
Fred Drake <fdrake@acm.org>
parents: 31282
diff changeset
1154 mutate, or even inspect, the list is undefined. The C
3894654b4848 fix a variety of markup bugs
Fred Drake <fdrake@acm.org>
parents: 31282
diff changeset
1155 implementation of Python 2.3 and newer makes the list appear empty
3894654b4848 fix a variety of markup bugs
Fred Drake <fdrake@acm.org>
parents: 31282
diff changeset
1156 for the duration, and raises \exception{ValueError} if it can detect
3894654b4848 fix a variety of markup bugs
Fred Drake <fdrake@acm.org>
parents: 31282
diff changeset
1157 that the list has been mutated during a sort.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1158 \end{description}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1159
31008
4224d807911c * Checkin remaining documentation
Raymond Hettinger <python@rcn.com>
parents: 30813
diff changeset
1160 \subsection{Set Types \label{types-set}}
4224d807911c * Checkin remaining documentation
Raymond Hettinger <python@rcn.com>
parents: 30813
diff changeset
1161 \obindex{set}
4224d807911c * Checkin remaining documentation
Raymond Hettinger <python@rcn.com>
parents: 30813
diff changeset
1162
4224d807911c * Checkin remaining documentation
Raymond Hettinger <python@rcn.com>
parents: 30813
diff changeset
1163 A \dfn{set} object is an unordered collection of immutable values.
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diff changeset
1164 Common uses include membership testing, removing duplicates from a sequence,
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diff changeset
1165 and computing mathematical operations such as intersection, union, difference,
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1166 and symmetric difference.
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diff changeset
1167 \versionadded{2.4}
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diff changeset
1168
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diff changeset
1169 Like other collections, sets support \code{\var{x} in \var{set}},
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diff changeset
1170 \code{len(\var{set})}, and \code{for \var{x} in \var{set}}. Being an
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1171 unordered collection, sets do not record element position or order of
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1172 insertion. Accordingly, sets do not support indexing, slicing, or
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1173 other sequence-like behavior.
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1174
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1175 There are currently two builtin set types, \class{set} and \class{frozenset}.
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1176 The \class{set} type is mutable --- the contents can be changed using methods
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1177 like \method{add()} and \method{remove()}. Since it is mutable, it has no
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1178 hash value and cannot be used as either a dictionary key or as an element of
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diff changeset
1179 another set. The \class{frozenset} type is immutable and hashable --- its
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diff changeset
1180 contents cannot be altered after is created; however, it can be used as
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diff changeset
1181 a dictionary key or as an element of another set.
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1182
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diff changeset
1183 Instances of \class{set} and \class{frozenset} provide the following operations:
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1184
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diff changeset
1185 \begin{tableiii}{c|c|l}{code}{Operation}{Equivalent}{Result}
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diff changeset
1186 \lineiii{len(\var{s})}{}{cardinality of set \var{s}}
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diff changeset
1187
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diff changeset
1188 \hline
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diff changeset
1189 \lineiii{\var{x} in \var{s}}{}
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diff changeset
1190 {test \var{x} for membership in \var{s}}
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diff changeset
1191 \lineiii{\var{x} not in \var{s}}{}
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diff changeset
1192 {test \var{x} for non-membership in \var{s}}
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parents: 30813
diff changeset
1193 \lineiii{\var{s}.issubset(\var{t})}{\code{\var{s} <= \var{t}}}
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diff changeset
1194 {test whether every element in \var{s} is in \var{t}}
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parents: 30813
diff changeset
1195 \lineiii{\var{s}.issuperset(\var{t})}{\code{\var{s} >= \var{t}}}
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diff changeset
1196 {test whether every element in \var{t} is in \var{s}}
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diff changeset
1197
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diff changeset
1198 \hline
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diff changeset
1199 \lineiii{\var{s}.union(\var{t})}{\var{s} | \var{t}}
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diff changeset
1200 {new set with elements from both \var{s} and \var{t}}
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diff changeset
1201 \lineiii{\var{s}.intersection(\var{t})}{\var{s} \&\ \var{t}}
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diff changeset
1202 {new set with elements common to \var{s} and \var{t}}
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diff changeset
1203 \lineiii{\var{s}.difference(\var{t})}{\var{s} - \var{t}}
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diff changeset
1204 {new set with elements in \var{s} but not in \var{t}}
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diff changeset
1205 \lineiii{\var{s}.symmetric_difference(\var{t})}{\var{s} \^\ \var{t}}
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parents: 30813
diff changeset
1206 {new set with elements in either \var{s} or \var{t} but not both}
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1207 \lineiii{\var{s}.copy()}{}
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diff changeset
1208 {new set with a shallow copy of \var{s}}
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diff changeset
1209 \end{tableiii}
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diff changeset
1210
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diff changeset
1211 Note, the non-operator versions of \method{union()}, \method{intersection()},
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1212 \method{difference()}, and \method{symmetric_difference()},
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diff changeset
1213 \method{issubset()}, and \method{issuperset()} methods will accept any
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diff changeset
1214 iterable as an argument. In contrast, their operator based counterparts
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diff changeset
1215 require their arguments to be sets. This precludes error-prone constructions
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diff changeset
1216 like \code{set('abc') \&\ 'cbs'} in favor of the more readable
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diff changeset
1217 \code{set('abc').intersection('cbs')}.
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diff changeset
1218
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diff changeset
1219 Both \class{set} and \class{frozenset} support set to set comparisons.
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1220 Two sets are equal if and only if every element of each set is contained in
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1221 the other (each is a subset of the other).
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1222 A set is less than another set if and only if the first set is a proper
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1223 subset of the second set (is a subset, but is not equal).
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diff changeset
1224 A set is greater than another set if and only if the first set is a proper
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diff changeset
1225 superset of the second set (is a superset, but is not equal).
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diff changeset
1226
34296
67f2190e1f6d SF Patch #1093896: miscellaneous doc typos
Raymond Hettinger <python@rcn.com>
parents: 34078
diff changeset
1227 Instances of \class{set} are compared to instances of \class{frozenset} based
32795
46e0431c9701 SF bug #995983 and #995987: Documentation nits.
Raymond Hettinger <python@rcn.com>
parents: 32459
diff changeset
1228 on their members. For example, \samp{set('abc') == frozenset('abc')} returns
46e0431c9701 SF bug #995983 and #995987: Documentation nits.
Raymond Hettinger <python@rcn.com>
parents: 32459
diff changeset
1229 \code{True}.
46e0431c9701 SF bug #995983 and #995987: Documentation nits.
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diff changeset
1230
31008
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diff changeset
1231 The subset and equality comparisons do not generalize to a complete
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diff changeset
1232 ordering function. For example, any two disjoint sets are not equal and
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diff changeset
1233 are not subsets of each other, so \emph{all} of the following return
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1234 \code{False}: \code{\var{a}<\var{b}}, \code{\var{a}==\var{b}}, or
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diff changeset
1235 \code{\var{a}>\var{b}}.
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diff changeset
1236 Accordingly, sets do not implement the \method{__cmp__} method.
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diff changeset
1237
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diff changeset
1238 Since sets only define partial ordering (subset relationships), the output
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diff changeset
1239 of the \method{list.sort()} method is undefined for lists of sets.
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diff changeset
1240
34898
fbcb1da480dd SF bug #1179957: Missing def'n of equality for set element
Raymond Hettinger <python@rcn.com>
parents: 34573
diff changeset
1241 Set elements are like dictionary keys; they need to define both
fbcb1da480dd SF bug #1179957: Missing def'n of equality for set element
Raymond Hettinger <python@rcn.com>
parents: 34573
diff changeset
1242 \method{__hash__} and \method{__eq__} methods.
fbcb1da480dd SF bug #1179957: Missing def'n of equality for set element
Raymond Hettinger <python@rcn.com>
parents: 34573
diff changeset
1243
32795
46e0431c9701 SF bug #995983 and #995987: Documentation nits.
Raymond Hettinger <python@rcn.com>
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diff changeset
1244 Binary operations that mix \class{set} instances with \class{frozenset}
46e0431c9701 SF bug #995983 and #995987: Documentation nits.
Raymond Hettinger <python@rcn.com>
parents: 32459
diff changeset
1245 return the type of the first operand. For example:
46e0431c9701 SF bug #995983 and #995987: Documentation nits.
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parents: 32459
diff changeset
1246 \samp{frozenset('ab') | set('bc')} returns an instance of \class{frozenset}.
31008
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diff changeset
1247
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diff changeset
1248 The following table lists operations available for \class{set}
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diff changeset
1249 that do not apply to immutable instances of \class{frozenset}:
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diff changeset
1250
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diff changeset
1251 \begin{tableiii}{c|c|l}{code}{Operation}{Equivalent}{Result}
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diff changeset
1252 \lineiii{\var{s}.update(\var{t})}
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diff changeset
1253 {\var{s} |= \var{t}}
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diff changeset
1254 {return set \var{s} with elements added from \var{t}}
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diff changeset
1255 \lineiii{\var{s}.intersection_update(\var{t})}
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diff changeset
1256 {\var{s} \&= \var{t}}
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diff changeset
1257 {return set \var{s} keeping only elements also found in \var{t}}
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diff changeset
1258 \lineiii{\var{s}.difference_update(\var{t})}
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diff changeset
1259 {\var{s} -= \var{t}}
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diff changeset
1260 {return set \var{s} after removing elements found in \var{t}}
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diff changeset
1261 \lineiii{\var{s}.symmetric_difference_update(\var{t})}
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diff changeset
1262 {\var{s} \textasciicircum= \var{t}}
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diff changeset
1263 {return set \var{s} with elements from \var{s} or \var{t}
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diff changeset
1264 but not both}
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diff changeset
1265
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diff changeset
1266 \hline
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diff changeset
1267 \lineiii{\var{s}.add(\var{x})}{}
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diff changeset
1268 {add element \var{x} to set \var{s}}
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diff changeset
1269 \lineiii{\var{s}.remove(\var{x})}{}
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diff changeset
1270 {remove \var{x} from set \var{s}; raises KeyError if not present}
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diff changeset
1271 \lineiii{\var{s}.discard(\var{x})}{}
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diff changeset
1272 {removes \var{x} from set \var{s} if present}
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diff changeset
1273 \lineiii{\var{s}.pop()}{}
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diff changeset
1274 {remove and return an arbitrary element from \var{s}; raises
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diff changeset
1275 \exception{KeyError} if empty}
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diff changeset
1276 \lineiii{\var{s}.clear()}{}
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diff changeset
1277 {remove all elements from set \var{s}}
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diff changeset
1278 \end{tableiii}
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diff changeset
1279
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diff changeset
1280 Note, the non-operator versions of the \method{update()},
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diff changeset
1281 \method{intersection_update()}, \method{difference_update()}, and
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diff changeset
1282 \method{symmetric_difference_update()} methods will accept any iterable
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1283 as an argument.
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diff changeset
1284
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
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parents:
diff changeset
1285
9083
bc41e86c938c Markup nits.
Fred Drake <fdrake@acm.org>
parents: 9034
diff changeset
1286 \subsection{Mapping Types \label{typesmapping}}
15005
0cf5111bf09c Use \obindex{...} instead of \indexii{...}{type} in many places; this is
Fred Drake <fdrake@acm.org>
parents: 14710
diff changeset
1287 \obindex{mapping}
0cf5111bf09c Use \obindex{...} instead of \indexii{...}{type} in many places; this is
Fred Drake <fdrake@acm.org>
parents: 14710
diff changeset
1288 \obindex{dictionary}
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8a306dfd9f33 Move files around to get the names to match the module names except for
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parents:
diff changeset
1289
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
1290 A \dfn{mapping} object maps immutable values to
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
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parents:
diff changeset
1291 arbitrary objects. Mappings are mutable objects. There is currently
8a306dfd9f33 Move files around to get the names to match the module names except for
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parents:
diff changeset
1292 only one standard mapping type, the \dfn{dictionary}. A dictionary's keys are
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
1293 almost arbitrary values. Only values containing lists, dictionaries
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
1294 or other mutable types (that are compared by value rather than by
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
1295 object identity) may not be used as keys.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
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parents:
diff changeset
1296 Numeric types used for keys obey the normal rules for numeric
30413
53f1c32ee69d SF bug #804280: fromkeys is not listed in index
Raymond Hettinger <python@rcn.com>
parents: 30375
diff changeset
1297 comparison: if two numbers compare equal (such as \code{1} and
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
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parents:
diff changeset
1298 \code{1.0}) then they can be used interchangeably to index the same
8a306dfd9f33 Move files around to get the names to match the module names except for
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parents:
diff changeset
1299 dictionary entry.
8a306dfd9f33 Move files around to get the names to match the module names except for
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parents:
diff changeset
1300
8a306dfd9f33 Move files around to get the names to match the module names except for
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parents:
diff changeset
1301 Dictionaries are created by placing a comma-separated list of
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1302 \code{\var{key}: \var{value}} pairs within braces, for example:
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1303 \code{\{'jack': 4098, 'sjoerd': 4127\}} or
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1304 \code{\{4098: 'jack', 4127: 'sjoerd'\}}.
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1305
10968
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1306 The following operations are defined on mappings (where \var{a} and
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1307 \var{b} are mappings, \var{k} is a key, and \var{v} and \var{x} are
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1308 arbitrary objects):
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1309 \indexiii{operations on}{mapping}{types}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1310 \indexiii{operations on}{dictionary}{type}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1311 \stindex{del}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1312 \bifuncindex{len}
10156
0f7d694bc334 Make sure all HTML pages generated from this section have reasonable
Fred Drake <fdrake@acm.org>
parents: 10147
diff changeset
1313 \withsubitem{(dictionary method)}{
0f7d694bc334 Make sure all HTML pages generated from this section have reasonable
Fred Drake <fdrake@acm.org>
parents: 10147
diff changeset
1314 \ttindex{clear()}
0f7d694bc334 Make sure all HTML pages generated from this section have reasonable
Fred Drake <fdrake@acm.org>
parents: 10147
diff changeset
1315 \ttindex{copy()}
0f7d694bc334 Make sure all HTML pages generated from this section have reasonable
Fred Drake <fdrake@acm.org>
parents: 10147
diff changeset
1316 \ttindex{has_key()}
30413
53f1c32ee69d SF bug #804280: fromkeys is not listed in index
Raymond Hettinger <python@rcn.com>
parents: 30375
diff changeset
1317 \ttindex{fromkeys()}
10156
0f7d694bc334 Make sure all HTML pages generated from this section have reasonable
Fred Drake <fdrake@acm.org>
parents: 10147
diff changeset
1318 \ttindex{items()}
0f7d694bc334 Make sure all HTML pages generated from this section have reasonable
Fred Drake <fdrake@acm.org>
parents: 10147
diff changeset
1319 \ttindex{keys()}
0f7d694bc334 Make sure all HTML pages generated from this section have reasonable
Fred Drake <fdrake@acm.org>
parents: 10147
diff changeset
1320 \ttindex{update()}
0f7d694bc334 Make sure all HTML pages generated from this section have reasonable
Fred Drake <fdrake@acm.org>
parents: 10147
diff changeset
1321 \ttindex{values()}
28171
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1322 \ttindex{get()}
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1323 \ttindex{setdefault()}
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1324 \ttindex{pop()}
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1325 \ttindex{popitem()}
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1326 \ttindex{iteritems()}
29067
04065c4a1c6b Missing parenthesis found by texcheck.py
Raymond Hettinger <python@rcn.com>
parents: 29065
diff changeset
1327 \ttindex{iterkeys()}
28171
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1328 \ttindex{itervalues()}}
10968
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1329
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1330 \begin{tableiii}{c|l|c}{code}{Operation}{Result}{Notes}
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1331 \lineiii{len(\var{a})}{the number of items in \var{a}}{}
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1332 \lineiii{\var{a}[\var{k}]}{the item of \var{a} with key \var{k}}{(1)}
13764
fdbc8730d356 Two minor nits from Gerry Weiner (no working email address) about
Fred Drake <fdrake@acm.org>
parents: 13222
diff changeset
1333 \lineiii{\var{a}[\var{k}] = \var{v}}
fdbc8730d356 Two minor nits from Gerry Weiner (no working email address) about
Fred Drake <fdrake@acm.org>
parents: 13222
diff changeset
1334 {set \code{\var{a}[\var{k}]} to \var{v}}
10968
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1335 {}
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1336 \lineiii{del \var{a}[\var{k}]}
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1337 {remove \code{\var{a}[\var{k}]} from \var{a}}
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1338 {(1)}
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1339 \lineiii{\var{a}.clear()}{remove all items from \code{a}}{}
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1340 \lineiii{\var{a}.copy()}{a (shallow) copy of \code{a}}{}
17616
7acba78e1e09 At the suggestion of Peter Funk, document 'key in dict' and 'key not
Guido van Rossum <guido@python.org>
parents: 17612
diff changeset
1341 \lineiii{\var{a}.has_key(\var{k})}
30095
e3c9b48de60a SF bug #775836: change 0,1 to False,True in dict.has_key doc
Raymond Hettinger <python@rcn.com>
parents: 29893
diff changeset
1342 {\code{True} if \var{a} has a key \var{k}, else \code{False}}
17594
bf94af396b1e Implement, test and document "key in dict" and "key not in dict".
Guido van Rossum <guido@python.org>
parents: 16778
diff changeset
1343 {}
17616
7acba78e1e09 At the suggestion of Peter Funk, document 'key in dict' and 'key not
Guido van Rossum <guido@python.org>
parents: 17612
diff changeset
1344 \lineiii{\var{k} \code{in} \var{a}}
7acba78e1e09 At the suggestion of Peter Funk, document 'key in dict' and 'key not
Guido van Rossum <guido@python.org>
parents: 17612
diff changeset
1345 {Equivalent to \var{a}.has_key(\var{k})}
17966
178bedf9536d Add descriptions of {}.iteritems(), {}.iterkeys(), and {}.itervalues()
Fred Drake <fdrake@acm.org>
parents: 17663
diff changeset
1346 {(2)}
17594
bf94af396b1e Implement, test and document "key in dict" and "key not in dict".
Guido van Rossum <guido@python.org>
parents: 16778
diff changeset
1347 \lineiii{\var{k} not in \var{a}}
17616
7acba78e1e09 At the suggestion of Peter Funk, document 'key in dict' and 'key not
Guido van Rossum <guido@python.org>
parents: 17612
diff changeset
1348 {Equivalent to \code{not} \var{a}.has_key(\var{k})}
17966
178bedf9536d Add descriptions of {}.iteritems(), {}.iterkeys(), and {}.itervalues()
Fred Drake <fdrake@acm.org>
parents: 17663
diff changeset
1349 {(2)}
10968
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1350 \lineiii{\var{a}.items()}
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1351 {a copy of \var{a}'s list of (\var{key}, \var{value}) pairs}
17966
178bedf9536d Add descriptions of {}.iteritems(), {}.iterkeys(), and {}.itervalues()
Fred Drake <fdrake@acm.org>
parents: 17663
diff changeset
1352 {(3)}
18085
7e459fb3c332 Fixed reference to table notes for {}.keys() and {}.items() -- these
Fred Drake <fdrake@acm.org>
parents: 17966
diff changeset
1353 \lineiii{\var{a}.keys()}{a copy of \var{a}'s list of keys}{(3)}
31616
5b3898d9ba59 SF #904720: dict.update should take a 2-tuple sequence like dict.__init_
Raymond Hettinger <python@rcn.com>
parents: 31357
diff changeset
1354 \lineiii{\var{a}.update(\optional{\var{b}})}
5b3898d9ba59 SF #904720: dict.update should take a 2-tuple sequence like dict.__init_
Raymond Hettinger <python@rcn.com>
parents: 31357
diff changeset
1355 {updates (and overwrites) key/value pairs from \var{b}}
5b3898d9ba59 SF #904720: dict.update should take a 2-tuple sequence like dict.__init_
Raymond Hettinger <python@rcn.com>
parents: 31357
diff changeset
1356 {(9)}
26437
57d03375aead SF Patch 643443. Added dict.fromkeys(iterable, value=None), a class
Raymond Hettinger <python@rcn.com>
parents: 26260
diff changeset
1357 \lineiii{\var{a}.fromkeys(\var{seq}\optional{, \var{value}})}
57d03375aead SF Patch 643443. Added dict.fromkeys(iterable, value=None), a class
Raymond Hettinger <python@rcn.com>
parents: 26260
diff changeset
1358 {Creates a new dictionary with keys from \var{seq} and values set to \var{value}}
57d03375aead SF Patch 643443. Added dict.fromkeys(iterable, value=None), a class
Raymond Hettinger <python@rcn.com>
parents: 26260
diff changeset
1359 {(7)}
18085
7e459fb3c332 Fixed reference to table notes for {}.keys() and {}.items() -- these
Fred Drake <fdrake@acm.org>
parents: 17966
diff changeset
1360 \lineiii{\var{a}.values()}{a copy of \var{a}'s list of values}{(3)}
10968
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1361 \lineiii{\var{a}.get(\var{k}\optional{, \var{x}})}
17603
d638e419c304 Fix a number of minor markup errors.
Fred Drake <fdrake@acm.org>
parents: 17594
diff changeset
1362 {\code{\var{a}[\var{k}]} if \code{\var{k} in \var{a}},
10968
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1363 else \var{x}}
18286
bc05a95242a3 Remove the restriction on a mapping's .update() method.
Barry Warsaw <barry@python.org>
parents: 18085
diff changeset
1364 {(4)}
13894
77b9e041b595 Barry's patch to document the new setdefault() method. Slightly
Guido van Rossum <guido@python.org>
parents: 13780
diff changeset
1365 \lineiii{\var{a}.setdefault(\var{k}\optional{, \var{x}})}
17603
d638e419c304 Fix a number of minor markup errors.
Fred Drake <fdrake@acm.org>
parents: 17594
diff changeset
1366 {\code{\var{a}[\var{k}]} if \code{\var{k} in \var{a}},
13894
77b9e041b595 Barry's patch to document the new setdefault() method. Slightly
Guido van Rossum <guido@python.org>
parents: 13780
diff changeset
1367 else \var{x} (also setting it)}
18286
bc05a95242a3 Remove the restriction on a mapping's .update() method.
Barry Warsaw <barry@python.org>
parents: 18085
diff changeset
1368 {(5)}
28211
92e3b611dc9f SF patch #693753: fix for bug 639806: default for dict.pop
Raymond Hettinger <python@rcn.com>
parents: 28171
diff changeset
1369 \lineiii{\var{a}.pop(\var{k}\optional{, \var{x}})}
92e3b611dc9f SF patch #693753: fix for bug 639806: default for dict.pop
Raymond Hettinger <python@rcn.com>
parents: 28171
diff changeset
1370 {\code{\var{a}[\var{k}]} if \code{\var{k} in \var{a}},
92e3b611dc9f SF patch #693753: fix for bug 639806: default for dict.pop
Raymond Hettinger <python@rcn.com>
parents: 28171
diff changeset
1371 else \var{x} (and remove k)}
92e3b611dc9f SF patch #693753: fix for bug 639806: default for dict.pop
Raymond Hettinger <python@rcn.com>
parents: 28171
diff changeset
1372 {(8)}
15522
aaa54752e4ba "Documentation" for {}.popitem().
Guido van Rossum <guido@python.org>
parents: 15463
diff changeset
1373 \lineiii{\var{a}.popitem()}
aaa54752e4ba "Documentation" for {}.popitem().
Guido van Rossum <guido@python.org>
parents: 15463
diff changeset
1374 {remove and return an arbitrary (\var{key}, \var{value}) pair}
18286
bc05a95242a3 Remove the restriction on a mapping's .update() method.
Barry Warsaw <barry@python.org>
parents: 18085
diff changeset
1375 {(6)}
17966
178bedf9536d Add descriptions of {}.iteritems(), {}.iterkeys(), and {}.itervalues()
Fred Drake <fdrake@acm.org>
parents: 17663
diff changeset
1376 \lineiii{\var{a}.iteritems()}
178bedf9536d Add descriptions of {}.iteritems(), {}.iterkeys(), and {}.itervalues()
Fred Drake <fdrake@acm.org>
parents: 17663
diff changeset
1377 {return an iterator over (\var{key}, \var{value}) pairs}
24902
f57d6db423f2 Extend some comments on the order of values in the returns from
Fred Drake <fdrake@acm.org>
parents: 24631
diff changeset
1378 {(2), (3)}
17966
178bedf9536d Add descriptions of {}.iteritems(), {}.iterkeys(), and {}.itervalues()
Fred Drake <fdrake@acm.org>
parents: 17663
diff changeset
1379 \lineiii{\var{a}.iterkeys()}
178bedf9536d Add descriptions of {}.iteritems(), {}.iterkeys(), and {}.itervalues()
Fred Drake <fdrake@acm.org>
parents: 17663
diff changeset
1380 {return an iterator over the mapping's keys}
24902
f57d6db423f2 Extend some comments on the order of values in the returns from
Fred Drake <fdrake@acm.org>
parents: 24631
diff changeset
1381 {(2), (3)}
17966
178bedf9536d Add descriptions of {}.iteritems(), {}.iterkeys(), and {}.itervalues()
Fred Drake <fdrake@acm.org>
parents: 17663
diff changeset
1382 \lineiii{\var{a}.itervalues()}
178bedf9536d Add descriptions of {}.iteritems(), {}.iterkeys(), and {}.itervalues()
Fred Drake <fdrake@acm.org>
parents: 17663
diff changeset
1383 {return an iterator over the mapping's values}
24902
f57d6db423f2 Extend some comments on the order of values in the returns from
Fred Drake <fdrake@acm.org>
parents: 24631
diff changeset
1384 {(2), (3)}
10968
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1385 \end{tableiii}
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1386
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1387 \noindent
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1388 Notes:
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1389 \begin{description}
10968
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1390 \item[(1)] Raises a \exception{KeyError} exception if \var{k} is not
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1391 in the map.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1392
17966
178bedf9536d Add descriptions of {}.iteritems(), {}.iterkeys(), and {}.itervalues()
Fred Drake <fdrake@acm.org>
parents: 17663
diff changeset
1393 \item[(2)] \versionadded{2.2}
178bedf9536d Add descriptions of {}.iteritems(), {}.iterkeys(), and {}.itervalues()
Fred Drake <fdrake@acm.org>
parents: 17663
diff changeset
1394
34029
81a1f754d32c Clarify the ordering of dictionary keys.
Raymond Hettinger <python@rcn.com>
parents: 33970
diff changeset
1395 \item[(3)] Keys and values are listed in an arbitrary order which is
81a1f754d32c Clarify the ordering of dictionary keys.
Raymond Hettinger <python@rcn.com>
parents: 33970
diff changeset
1396 non-random, varies across Python implementations, and depends on the
81a1f754d32c Clarify the ordering of dictionary keys.
Raymond Hettinger <python@rcn.com>
parents: 33970
diff changeset
1397 dictionary's history of insertions and deletions.
81a1f754d32c Clarify the ordering of dictionary keys.
Raymond Hettinger <python@rcn.com>
parents: 33970
diff changeset
1398 If \method{items()}, \method{keys()}, \method{values()},
24902
f57d6db423f2 Extend some comments on the order of values in the returns from
Fred Drake <fdrake@acm.org>
parents: 24631
diff changeset
1399 \method{iteritems()}, \method{iterkeys()}, and \method{itervalues()}
f57d6db423f2 Extend some comments on the order of values in the returns from
Fred Drake <fdrake@acm.org>
parents: 24631
diff changeset
1400 are called with no intervening modifications to the dictionary, the
f57d6db423f2 Extend some comments on the order of values in the returns from
Fred Drake <fdrake@acm.org>
parents: 24631
diff changeset
1401 lists will directly correspond. This allows the creation of
f57d6db423f2 Extend some comments on the order of values in the returns from
Fred Drake <fdrake@acm.org>
parents: 24631
diff changeset
1402 \code{(\var{value}, \var{key})} pairs using \function{zip()}:
f57d6db423f2 Extend some comments on the order of values in the returns from
Fred Drake <fdrake@acm.org>
parents: 24631
diff changeset
1403 \samp{pairs = zip(\var{a}.values(), \var{a}.keys())}. The same
f57d6db423f2 Extend some comments on the order of values in the returns from
Fred Drake <fdrake@acm.org>
parents: 24631
diff changeset
1404 relationship holds for the \method{iterkeys()} and
f57d6db423f2 Extend some comments on the order of values in the returns from
Fred Drake <fdrake@acm.org>
parents: 24631
diff changeset
1405 \method{itervalues()} methods: \samp{pairs = zip(\var{a}.itervalues(),
f57d6db423f2 Extend some comments on the order of values in the returns from
Fred Drake <fdrake@acm.org>
parents: 24631
diff changeset
1406 \var{a}.iterkeys())} provides the same value for \code{pairs}.
f57d6db423f2 Extend some comments on the order of values in the returns from
Fred Drake <fdrake@acm.org>
parents: 24631
diff changeset
1407 Another way to create the same list is \samp{pairs = [(v, k) for (k,
f57d6db423f2 Extend some comments on the order of values in the returns from
Fred Drake <fdrake@acm.org>
parents: 24631
diff changeset
1408 v) in \var{a}.iteritems()]}.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1409
18286
bc05a95242a3 Remove the restriction on a mapping's .update() method.
Barry Warsaw <barry@python.org>
parents: 18085
diff changeset
1410 \item[(4)] Never raises an exception if \var{k} is not in the map,
12223
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
1411 instead it returns \var{x}. \var{x} is optional; when \var{x} is not
10968
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1412 provided and \var{k} is not in the map, \code{None} is returned.
13894
77b9e041b595 Barry's patch to document the new setdefault() method. Slightly
Guido van Rossum <guido@python.org>
parents: 13780
diff changeset
1413
18286
bc05a95242a3 Remove the restriction on a mapping's .update() method.
Barry Warsaw <barry@python.org>
parents: 18085
diff changeset
1414 \item[(5)] \function{setdefault()} is like \function{get()}, except
13894
77b9e041b595 Barry's patch to document the new setdefault() method. Slightly
Guido van Rossum <guido@python.org>
parents: 13780
diff changeset
1415 that if \var{k} is missing, \var{x} is both returned and inserted into
33003
b5dcfe7a4159 Point out that the setdefault defaults the value to None. Inspired by
Michael W. Hudson <mwh@python.net>
parents: 32975
diff changeset
1416 the dictionary as the value of \var{k}. \var{x} defaults to \var{None}.
15522
aaa54752e4ba "Documentation" for {}.popitem().
Guido van Rossum <guido@python.org>
parents: 15463
diff changeset
1417
18286
bc05a95242a3 Remove the restriction on a mapping's .update() method.
Barry Warsaw <barry@python.org>
parents: 18085
diff changeset
1418 \item[(6)] \function{popitem()} is useful to destructively iterate
34969
672e5f65172c SF bug #1209671: dict.popitem documentation should mention empty dict case
Raymond Hettinger <python@rcn.com>
parents: 34917
diff changeset
1419 over a dictionary, as often used in set algorithms. If the dictionary
672e5f65172c SF bug #1209671: dict.popitem documentation should mention empty dict case
Raymond Hettinger <python@rcn.com>
parents: 34917
diff changeset
1420 is empty, calling \function{popitem()} raises a \exception{KeyError}.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1421
26437
57d03375aead SF Patch 643443. Added dict.fromkeys(iterable, value=None), a class
Raymond Hettinger <python@rcn.com>
parents: 26260
diff changeset
1422 \item[(7)] \function{fromkeys()} is a class method that returns a
57d03375aead SF Patch 643443. Added dict.fromkeys(iterable, value=None), a class
Raymond Hettinger <python@rcn.com>
parents: 26260
diff changeset
1423 new dictionary. \var{value} defaults to \code{None}. \versionadded{2.3}
28211
92e3b611dc9f SF patch #693753: fix for bug 639806: default for dict.pop
Raymond Hettinger <python@rcn.com>
parents: 28171
diff changeset
1424
92e3b611dc9f SF patch #693753: fix for bug 639806: default for dict.pop
Raymond Hettinger <python@rcn.com>
parents: 28171
diff changeset
1425 \item[(8)] \function{pop()} raises a \exception{KeyError} when no default
92e3b611dc9f SF patch #693753: fix for bug 639806: default for dict.pop
Raymond Hettinger <python@rcn.com>
parents: 28171
diff changeset
1426 value is given and the key is not found. \versionadded{2.3}
26437
57d03375aead SF Patch 643443. Added dict.fromkeys(iterable, value=None), a class
Raymond Hettinger <python@rcn.com>
parents: 26260
diff changeset
1427
31616
5b3898d9ba59 SF #904720: dict.update should take a 2-tuple sequence like dict.__init_
Raymond Hettinger <python@rcn.com>
parents: 31357
diff changeset
1428 \item[(9)] \function{update()} accepts either another mapping object
5b3898d9ba59 SF #904720: dict.update should take a 2-tuple sequence like dict.__init_
Raymond Hettinger <python@rcn.com>
parents: 31357
diff changeset
1429 or an iterable of key/value pairs (as a tuple or other iterable of
5b3898d9ba59 SF #904720: dict.update should take a 2-tuple sequence like dict.__init_
Raymond Hettinger <python@rcn.com>
parents: 31357
diff changeset
1430 length two). If keyword arguments are specified, the mapping is
5b3898d9ba59 SF #904720: dict.update should take a 2-tuple sequence like dict.__init_
Raymond Hettinger <python@rcn.com>
parents: 31357
diff changeset
1431 then is updated with those key/value pairs:
5b3898d9ba59 SF #904720: dict.update should take a 2-tuple sequence like dict.__init_
Raymond Hettinger <python@rcn.com>
parents: 31357
diff changeset
1432 \samp{d.update(red=1, blue=2)}.
5b3898d9ba59 SF #904720: dict.update should take a 2-tuple sequence like dict.__init_
Raymond Hettinger <python@rcn.com>
parents: 31357
diff changeset
1433 \versionchanged[Allowed the argument to be an iterable of key/value
5b3898d9ba59 SF #904720: dict.update should take a 2-tuple sequence like dict.__init_
Raymond Hettinger <python@rcn.com>
parents: 31357
diff changeset
1434 pairs and allowed keyword arguments]{2.4}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1435
31631
228d264c5fbb SF Patch #912462: Relocate \end tag to the right place.
Hye-Shik Chang <hyeshik@gmail.com>
parents: 31616
diff changeset
1436 \end{description}
228d264c5fbb SF Patch #912462: Relocate \end tag to the right place.
Hye-Shik Chang <hyeshik@gmail.com>
parents: 31616
diff changeset
1437
20767
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1438 \subsection{File Objects
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1439 \label{bltin-file-objects}}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1440
20767
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1441 File objects\obindex{file} are implemented using C's \code{stdio}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1442 package and can be created with the built-in constructor
22241
7584b6f1afde Change Windows file.truncate() to (a) restore the original file position,
Tim Peters <tim.peters@gmail.com>
parents: 22214
diff changeset
1443 \function{file()}\bifuncindex{file} described in section
20764
37b8d92e12f5 Mention the new file() builtin in the section on file objects.
Tim Peters <tim.peters@gmail.com>
parents: 20701
diff changeset
1444 \ref{built-in-funcs}, ``Built-in Functions.''\footnote{\function{file()}
37b8d92e12f5 Mention the new file() builtin in the section on file objects.
Tim Peters <tim.peters@gmail.com>
parents: 20701
diff changeset
1445 is new in Python 2.2. The older built-in \function{open()} is an
31286
3894654b4848 fix a variety of markup bugs
Fred Drake <fdrake@acm.org>
parents: 31282
diff changeset
1446 alias for \function{file()}.} File objects are also returned
18416
33b4357aebb8 Fix up a few style nits -- avoid "e.g." and "i.e." -- these make
Fred Drake <fdrake@acm.org>
parents: 18395
diff changeset
1447 by some other built-in functions and methods, such as
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
1448 \function{os.popen()} and \function{os.fdopen()} and the
9461
9ffd604807c2 Don't describe something as "below"; that won't make sense for the
Fred Drake <fdrake@acm.org>
parents: 9318
diff changeset
1449 \method{makefile()} method of socket objects.
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
1450 \refstmodindex{os}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1451 \refbimodindex{socket}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1452
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1453 When a file operation fails for an I/O-related reason, the exception
9558
fa867d8ee7eb Remove some remaining {\rm ...} constructs.
Fred Drake <fdrake@acm.org>
parents: 9523
diff changeset
1454 \exception{IOError} is raised. This includes situations where the
fa867d8ee7eb Remove some remaining {\rm ...} constructs.
Fred Drake <fdrake@acm.org>
parents: 9523
diff changeset
1455 operation is not defined for some reason, like \method{seek()} on a tty
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1456 device or writing a file opened for reading.
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1457
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1458 Files have the following methods:
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1459
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1460
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1461 \begin{methoddesc}[file]{close}{}
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
1462 Close the file. A closed file cannot be read or written any more.
15383
eeb7c8a5b79f Document the proper exception to be raised by I/O operations on closed
Fred Drake <fdrake@acm.org>
parents: 15332
diff changeset
1463 Any operation which requires that the file be open will raise a
eeb7c8a5b79f Document the proper exception to be raised by I/O operations on closed
Fred Drake <fdrake@acm.org>
parents: 15332
diff changeset
1464 \exception{ValueError} after the file has been closed. Calling
14685
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1465 \method{close()} more than once is allowed.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1466 \end{methoddesc}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1467
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1468 \begin{methoddesc}[file]{flush}{}
14685
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1469 Flush the internal buffer, like \code{stdio}'s
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1470 \cfunction{fflush()}. This may be a no-op on some file-like
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1471 objects.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1472 \end{methoddesc}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1473
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1474 \begin{methoddesc}[file]{fileno}{}
14685
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1475 \index{file descriptor}
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1476 \index{descriptor, file}
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1477 Return the integer ``file descriptor'' that is used by the
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1478 underlying implementation to request I/O operations from the
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1479 operating system. This can be useful for other, lower level
18416
33b4357aebb8 Fix up a few style nits -- avoid "e.g." and "i.e." -- these make
Fred Drake <fdrake@acm.org>
parents: 18395
diff changeset
1480 interfaces that use file descriptors, such as the
33b4357aebb8 Fix up a few style nits -- avoid "e.g." and "i.e." -- these make
Fred Drake <fdrake@acm.org>
parents: 18395
diff changeset
1481 \refmodule{fcntl}\refbimodindex{fcntl} module or
20580
376ee174ecd0 Use the \note and \warning macros where appropriate.
Fred Drake <fdrake@acm.org>
parents: 20173
diff changeset
1482 \function{os.read()} and friends. \note{File-like objects
18416
33b4357aebb8 Fix up a few style nits -- avoid "e.g." and "i.e." -- these make
Fred Drake <fdrake@acm.org>
parents: 18395
diff changeset
1483 which do not have a real file descriptor should \emph{not} provide
20580
376ee174ecd0 Use the \note and \warning macros where appropriate.
Fred Drake <fdrake@acm.org>
parents: 20173
diff changeset
1484 this method!}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1485 \end{methoddesc}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1486
24599
d7ca0a2ce074 Document file.next(). Mark xreadlines obsolete (both method and
Guido van Rossum <guido@python.org>
parents: 24598
diff changeset
1487 \begin{methoddesc}[file]{isatty}{}
d7ca0a2ce074 Document file.next(). Mark xreadlines obsolete (both method and
Guido van Rossum <guido@python.org>
parents: 24598
diff changeset
1488 Return \code{True} if the file is connected to a tty(-like) device, else
d7ca0a2ce074 Document file.next(). Mark xreadlines obsolete (both method and
Guido van Rossum <guido@python.org>
parents: 24598
diff changeset
1489 \code{False}. \note{If a file-like object is not associated
d7ca0a2ce074 Document file.next(). Mark xreadlines obsolete (both method and
Guido van Rossum <guido@python.org>
parents: 24598
diff changeset
1490 with a real file, this method should \emph{not} be implemented.}
d7ca0a2ce074 Document file.next(). Mark xreadlines obsolete (both method and
Guido van Rossum <guido@python.org>
parents: 24598
diff changeset
1491 \end{methoddesc}
d7ca0a2ce074 Document file.next(). Mark xreadlines obsolete (both method and
Guido van Rossum <guido@python.org>
parents: 24598
diff changeset
1492
d7ca0a2ce074 Document file.next(). Mark xreadlines obsolete (both method and
Guido van Rossum <guido@python.org>
parents: 24598
diff changeset
1493 \begin{methoddesc}[file]{next}{}
30413
53f1c32ee69d SF bug #804280: fromkeys is not listed in index
Raymond Hettinger <python@rcn.com>
parents: 30375
diff changeset
1494 A file object is its own iterator, for example \code{iter(\var{f})} returns
24599
d7ca0a2ce074 Document file.next(). Mark xreadlines obsolete (both method and
Guido van Rossum <guido@python.org>
parents: 24598
diff changeset
1495 \var{f} (unless \var{f} is closed). When a file is used as an
d7ca0a2ce074 Document file.next(). Mark xreadlines obsolete (both method and
Guido van Rossum <guido@python.org>
parents: 24598
diff changeset
1496 iterator, typically in a \keyword{for} loop (for example,
d7ca0a2ce074 Document file.next(). Mark xreadlines obsolete (both method and
Guido van Rossum <guido@python.org>
parents: 24598
diff changeset
1497 \code{for line in f: print line}), the \method{next()} method is
d7ca0a2ce074 Document file.next(). Mark xreadlines obsolete (both method and
Guido van Rossum <guido@python.org>
parents: 24598
diff changeset
1498 called repeatedly. This method returns the next input line, or raises
d7ca0a2ce074 Document file.next(). Mark xreadlines obsolete (both method and
Guido van Rossum <guido@python.org>
parents: 24598
diff changeset
1499 \exception{StopIteration} when \EOF{} is hit. In order to make a
d7ca0a2ce074 Document file.next(). Mark xreadlines obsolete (both method and
Guido van Rossum <guido@python.org>
parents: 24598
diff changeset
1500 \keyword{for} loop the most efficient way of looping over the lines of
d7ca0a2ce074 Document file.next(). Mark xreadlines obsolete (both method and
Guido van Rossum <guido@python.org>
parents: 24598
diff changeset
1501 a file (a very common operation), the \method{next()} method uses a
d7ca0a2ce074 Document file.next(). Mark xreadlines obsolete (both method and
Guido van Rossum <guido@python.org>
parents: 24598
diff changeset
1502 hidden read-ahead buffer. As a consequence of using a read-ahead
d7ca0a2ce074 Document file.next(). Mark xreadlines obsolete (both method and
Guido van Rossum <guido@python.org>
parents: 24598
diff changeset
1503 buffer, combining \method{next()} with other file methods (like
d7ca0a2ce074 Document file.next(). Mark xreadlines obsolete (both method and
Guido van Rossum <guido@python.org>
parents: 24598
diff changeset
1504 \method{readline()}) does not work right. However, using
d7ca0a2ce074 Document file.next(). Mark xreadlines obsolete (both method and
Guido van Rossum <guido@python.org>
parents: 24598
diff changeset
1505 \method{seek()} to reposition the file to an absolute position will
d7ca0a2ce074 Document file.next(). Mark xreadlines obsolete (both method and
Guido van Rossum <guido@python.org>
parents: 24598
diff changeset
1506 flush the read-ahead buffer.
d7ca0a2ce074 Document file.next(). Mark xreadlines obsolete (both method and
Guido van Rossum <guido@python.org>
parents: 24598
diff changeset
1507 \versionadded{2.3}
d7ca0a2ce074 Document file.next(). Mark xreadlines obsolete (both method and
Guido van Rossum <guido@python.org>
parents: 24598
diff changeset
1508 \end{methoddesc}
d7ca0a2ce074 Document file.next(). Mark xreadlines obsolete (both method and
Guido van Rossum <guido@python.org>
parents: 24598
diff changeset
1509
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1510 \begin{methoddesc}[file]{read}{\optional{size}}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1511 Read at most \var{size} bytes from the file (less if the read hits
10606
fe5fcb7e73f7 Correct documentation for <file>.read(); Python makes a serious
Fred Drake <fdrake@acm.org>
parents: 10520
diff changeset
1512 \EOF{} before obtaining \var{size} bytes). If the \var{size}
fe5fcb7e73f7 Correct documentation for <file>.read(); Python makes a serious
Fred Drake <fdrake@acm.org>
parents: 10520
diff changeset
1513 argument is negative or omitted, read all data until \EOF{} is
fe5fcb7e73f7 Correct documentation for <file>.read(); Python makes a serious
Fred Drake <fdrake@acm.org>
parents: 10520
diff changeset
1514 reached. The bytes are returned as a string object. An empty
fe5fcb7e73f7 Correct documentation for <file>.read(); Python makes a serious
Fred Drake <fdrake@acm.org>
parents: 10520
diff changeset
1515 string is returned when \EOF{} is encountered immediately. (For
fe5fcb7e73f7 Correct documentation for <file>.read(); Python makes a serious
Fred Drake <fdrake@acm.org>
parents: 10520
diff changeset
1516 certain files, like ttys, it makes sense to continue reading after
fe5fcb7e73f7 Correct documentation for <file>.read(); Python makes a serious
Fred Drake <fdrake@acm.org>
parents: 10520
diff changeset
1517 an \EOF{} is hit.) Note that this method may call the underlying
fe5fcb7e73f7 Correct documentation for <file>.read(); Python makes a serious
Fred Drake <fdrake@acm.org>
parents: 10520
diff changeset
1518 C function \cfunction{fread()} more than once in an effort to
26672
8dd25a6f5913 Fixed bug
Gustavo Niemeyer <gustavo@niemeyer.net>
parents: 26592
diff changeset
1519 acquire as close to \var{size} bytes as possible. Also note that
8dd25a6f5913 Fixed bug
Gustavo Niemeyer <gustavo@niemeyer.net>
parents: 26592
diff changeset
1520 when in non-blocking mode, less data than what was requested may
8dd25a6f5913 Fixed bug
Gustavo Niemeyer <gustavo@niemeyer.net>
parents: 26592
diff changeset
1521 be returned, even if no \var{size} parameter was given.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1522 \end{methoddesc}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1523
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1524 \begin{methoddesc}[file]{readline}{\optional{size}}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1525 Read one entire line from the file. A trailing newline character is
31286
3894654b4848 fix a variety of markup bugs
Fred Drake <fdrake@acm.org>
parents: 31282
diff changeset
1526 kept in the string (but may be absent when a file ends with an
3894654b4848 fix a variety of markup bugs
Fred Drake <fdrake@acm.org>
parents: 31282
diff changeset
1527 incomplete line).\footnote{
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
1528 The advantage of leaving the newline on is that
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
1529 returning an empty string is then an unambiguous \EOF{}
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
1530 indication. It is also possible (in cases where it might
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
1531 matter, for example, if you
22241
7584b6f1afde Change Windows file.truncate() to (a) restore the original file position,
Tim Peters <tim.peters@gmail.com>
parents: 22214
diff changeset
1532 want to make an exact copy of a file while scanning its lines)
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
1533 to tell whether the last line of a file ended in a newline
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
1534 or not (yes this happens!).
31286
3894654b4848 fix a variety of markup bugs
Fred Drake <fdrake@acm.org>
parents: 31282
diff changeset
1535 } If the \var{size} argument is present and
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1536 non-negative, it is a maximum byte count (including the trailing
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1537 newline) and an incomplete line may be returned.
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
1538 An empty string is returned \emph{only} when \EOF{} is encountered
20580
376ee174ecd0 Use the \note and \warning macros where appropriate.
Fred Drake <fdrake@acm.org>
parents: 20173
diff changeset
1539 immediately. \note{Unlike \code{stdio}'s \cfunction{fgets()}, the
14685
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1540 returned string contains null characters (\code{'\e 0'}) if they
20580
376ee174ecd0 Use the \note and \warning macros where appropriate.
Fred Drake <fdrake@acm.org>
parents: 20173
diff changeset
1541 occurred in the input.}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1542 \end{methoddesc}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1543
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1544 \begin{methoddesc}[file]{readlines}{\optional{sizehint}}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1545 Read until \EOF{} using \method{readline()} and return a list containing
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1546 the lines thus read. If the optional \var{sizehint} argument is
21062
bc02c3b09626 Clean up some markup cruft. A number of the macros that take no
Fred Drake <fdrake@acm.org>
parents: 20767
diff changeset
1547 present, instead of reading up to \EOF, whole lines totalling
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1548 approximately \var{sizehint} bytes (possibly after rounding up to an
14685
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1549 internal buffer size) are read. Objects implementing a file-like
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1550 interface may choose to ignore \var{sizehint} if it cannot be
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1551 implemented, or cannot be implemented efficiently.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1552 \end{methoddesc}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1553
15926
ac13cef423c8 Document xreadlines() method. (Forgot to check this in before!)
Guido van Rossum <guido@python.org>
parents: 15896
diff changeset
1554 \begin{methoddesc}[file]{xreadlines}{}
24599
d7ca0a2ce074 Document file.next(). Mark xreadlines obsolete (both method and
Guido van Rossum <guido@python.org>
parents: 24598
diff changeset
1555 This method returns the same thing as \code{iter(f)}.
17612
c19d6db6e99b Only document <file>.xreadlines() once; added version annotation.
Fred Drake <fdrake@acm.org>
parents: 17603
diff changeset
1556 \versionadded{2.1}
31286
3894654b4848 fix a variety of markup bugs
Fred Drake <fdrake@acm.org>
parents: 31282
diff changeset
1557 \deprecated{2.3}{Use \samp{for \var{line} in \var{file}} instead.}
15926
ac13cef423c8 Document xreadlines() method. (Forgot to check this in before!)
Guido van Rossum <guido@python.org>
parents: 15896
diff changeset
1558 \end{methoddesc}
ac13cef423c8 Document xreadlines() method. (Forgot to check this in before!)
Guido van Rossum <guido@python.org>
parents: 15896
diff changeset
1559
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1560 \begin{methoddesc}[file]{seek}{offset\optional{, whence}}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1561 Set the file's current position, like \code{stdio}'s \cfunction{fseek()}.
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1562 The \var{whence} argument is optional and defaults to \code{0}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1563 (absolute file positioning); other values are \code{1} (seek
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1564 relative to the current position) and \code{2} (seek relative to the
15731
a06415994cb5 Added information about the interaction of opening a file in append mode
Fred Drake <fdrake@acm.org>
parents: 15522
diff changeset
1565 file's end). There is no return value. Note that if the file is
a06415994cb5 Added information about the interaction of opening a file in append mode
Fred Drake <fdrake@acm.org>
parents: 15522
diff changeset
1566 opened for appending (mode \code{'a'} or \code{'a+'}), any
a06415994cb5 Added information about the interaction of opening a file in append mode
Fred Drake <fdrake@acm.org>
parents: 15522
diff changeset
1567 \method{seek()} operations will be undone at the next write. If the
a06415994cb5 Added information about the interaction of opening a file in append mode
Fred Drake <fdrake@acm.org>
parents: 15522
diff changeset
1568 file is only opened for writing in append mode (mode \code{'a'}),
a06415994cb5 Added information about the interaction of opening a file in append mode
Fred Drake <fdrake@acm.org>
parents: 15522
diff changeset
1569 this method is essentially a no-op, but it remains useful for files
30705
3ff03446f362 Patch #809535: Mention behaviour of seek on text files. Backported to 2.3.
Martin v. Löwis <martin@v.loewis.de>
parents: 30697
diff changeset
1570 opened in append mode with reading enabled (mode \code{'a+'}). If the
3ff03446f362 Patch #809535: Mention behaviour of seek on text files. Backported to 2.3.
Martin v. Löwis <martin@v.loewis.de>
parents: 30697
diff changeset
1571 file is opened in text mode (mode \code{'t'}), only offsets returned
3ff03446f362 Patch #809535: Mention behaviour of seek on text files. Backported to 2.3.
Martin v. Löwis <martin@v.loewis.de>
parents: 30697
diff changeset
1572 by \method{tell()} are legal. Use of other offsets causes undefined
3ff03446f362 Patch #809535: Mention behaviour of seek on text files. Backported to 2.3.
Martin v. Löwis <martin@v.loewis.de>
parents: 30697
diff changeset
1573 behavior.
3ff03446f362 Patch #809535: Mention behaviour of seek on text files. Backported to 2.3.
Martin v. Löwis <martin@v.loewis.de>
parents: 30697
diff changeset
1574
3ff03446f362 Patch #809535: Mention behaviour of seek on text files. Backported to 2.3.
Martin v. Löwis <martin@v.loewis.de>
parents: 30697
diff changeset
1575 Note that not all file objects are seekable.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1576 \end{methoddesc}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1577
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1578 \begin{methoddesc}[file]{tell}{}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1579 Return the file's current position, like \code{stdio}'s
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1580 \cfunction{ftell()}.
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1581 \end{methoddesc}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1582
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1583 \begin{methoddesc}[file]{truncate}{\optional{size}}
22241
7584b6f1afde Change Windows file.truncate() to (a) restore the original file position,
Tim Peters <tim.peters@gmail.com>
parents: 22214
diff changeset
1584 Truncate the file's size. If the optional \var{size} argument is
14685
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1585 present, the file is truncated to (at most) that size. The size
22241
7584b6f1afde Change Windows file.truncate() to (a) restore the original file position,
Tim Peters <tim.peters@gmail.com>
parents: 22214
diff changeset
1586 defaults to the current position. The current file position is
7584b6f1afde Change Windows file.truncate() to (a) restore the original file position,
Tim Peters <tim.peters@gmail.com>
parents: 22214
diff changeset
1587 not changed. Note that if a specified size exceeds the file's
7584b6f1afde Change Windows file.truncate() to (a) restore the original file position,
Tim Peters <tim.peters@gmail.com>
parents: 22214
diff changeset
1588 current size, the result is platform-dependent: possibilities
7584b6f1afde Change Windows file.truncate() to (a) restore the original file position,
Tim Peters <tim.peters@gmail.com>
parents: 22214
diff changeset
1589 include that file may remain unchanged, increase to the specified
7584b6f1afde Change Windows file.truncate() to (a) restore the original file position,
Tim Peters <tim.peters@gmail.com>
parents: 22214
diff changeset
1590 size as if zero-filled, or increase to the specified size with
7584b6f1afde Change Windows file.truncate() to (a) restore the original file position,
Tim Peters <tim.peters@gmail.com>
parents: 22214
diff changeset
1591 undefined new content.
30375
4aa84a8b1fe4 Fix spacing markup and other sundries.
Raymond Hettinger <python@rcn.com>
parents: 30250
diff changeset
1592 Availability: Windows, many \UNIX{} variants.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1593 \end{methoddesc}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1594
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1595 \begin{methoddesc}[file]{write}{str}
20580
376ee174ecd0 Use the \note and \warning macros where appropriate.
Fred Drake <fdrake@acm.org>
parents: 20173
diff changeset
1596 Write a string to the file. There is no return value. Due to
15789
9e9556924b0a Added documentation for the xreadlines module & related changes. The
Fred Drake <fdrake@acm.org>
parents: 15731
diff changeset
1597 buffering, the string may not actually show up in the file until
9e9556924b0a Added documentation for the xreadlines module & related changes. The
Fred Drake <fdrake@acm.org>
parents: 15731
diff changeset
1598 the \method{flush()} or \method{close()} method is called.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1599 \end{methoddesc}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1600
20045
7b8c11739714 Generalize file.writelines() to allow iterable objects.
Tim Peters <tim.peters@gmail.com>
parents: 20031
diff changeset
1601 \begin{methoddesc}[file]{writelines}{sequence}
7b8c11739714 Generalize file.writelines() to allow iterable objects.
Tim Peters <tim.peters@gmail.com>
parents: 20031
diff changeset
1602 Write a sequence of strings to the file. The sequence can be any
7b8c11739714 Generalize file.writelines() to allow iterable objects.
Tim Peters <tim.peters@gmail.com>
parents: 20031
diff changeset
1603 iterable object producing strings, typically a list of strings.
7b8c11739714 Generalize file.writelines() to allow iterable objects.
Tim Peters <tim.peters@gmail.com>
parents: 20031
diff changeset
1604 There is no return value.
15789
9e9556924b0a Added documentation for the xreadlines module & related changes. The
Fred Drake <fdrake@acm.org>
parents: 15731
diff changeset
1605 (The name is intended to match \method{readlines()};
9e9556924b0a Added documentation for the xreadlines module & related changes. The
Fred Drake <fdrake@acm.org>
parents: 15731
diff changeset
1606 \method{writelines()} does not add line separators.)
9e9556924b0a Added documentation for the xreadlines module & related changes. The
Fred Drake <fdrake@acm.org>
parents: 15731
diff changeset
1607 \end{methoddesc}
9e9556924b0a Added documentation for the xreadlines module & related changes. The
Fred Drake <fdrake@acm.org>
parents: 15731
diff changeset
1608
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1609
20031
e5a3f9d7766b Note that files are iterable; describe what the iterator returns.
Fred Drake <fdrake@acm.org>
parents: 19529
diff changeset
1610 Files support the iterator protocol. Each iteration returns the same
e5a3f9d7766b Note that files are iterable; describe what the iterator returns.
Fred Drake <fdrake@acm.org>
parents: 19529
diff changeset
1611 result as \code{\var{file}.readline()}, and iteration ends when the
e5a3f9d7766b Note that files are iterable; describe what the iterator returns.
Fred Drake <fdrake@acm.org>
parents: 19529
diff changeset
1612 \method{readline()} method returns an empty string.
e5a3f9d7766b Note that files are iterable; describe what the iterator returns.
Fred Drake <fdrake@acm.org>
parents: 19529
diff changeset
1613
e5a3f9d7766b Note that files are iterable; describe what the iterator returns.
Fred Drake <fdrake@acm.org>
parents: 19529
diff changeset
1614
14685
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1615 File objects also offer a number of other interesting attributes.
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1616 These are not required for file-like objects, but should be
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1617 implemented if they make sense for the particular object.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1618
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1619 \begin{memberdesc}[file]{closed}
22920
2392af05f052 Update docs for bool changes by Guido around April 6
Neal Norwitz <nnorwitz@gmail.com>
parents: 22785
diff changeset
1620 bool indicating the current state of the file object. This is a
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1621 read-only attribute; the \method{close()} method changes the value.
14685
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1622 It may not be available on all file-like objects.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1623 \end{memberdesc}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1624
29065
bf1634b023d5 Patch #612627: Add encoding attribute to file objects, and determine
Martin v. Löwis <martin@v.loewis.de>
parents: 28909
diff changeset
1625 \begin{memberdesc}[file]{encoding}
bf1634b023d5 Patch #612627: Add encoding attribute to file objects, and determine
Martin v. Löwis <martin@v.loewis.de>
parents: 28909
diff changeset
1626 The encoding that this file uses. When Unicode strings are written
bf1634b023d5 Patch #612627: Add encoding attribute to file objects, and determine
Martin v. Löwis <martin@v.loewis.de>
parents: 28909
diff changeset
1627 to a file, they will be converted to byte strings using this encoding.
bf1634b023d5 Patch #612627: Add encoding attribute to file objects, and determine
Martin v. Löwis <martin@v.loewis.de>
parents: 28909
diff changeset
1628 In addition, when the file is connected to a terminal, the attribute
bf1634b023d5 Patch #612627: Add encoding attribute to file objects, and determine
Martin v. Löwis <martin@v.loewis.de>
parents: 28909
diff changeset
1629 gives the encoding that the terminal is likely to use (that
bf1634b023d5 Patch #612627: Add encoding attribute to file objects, and determine
Martin v. Löwis <martin@v.loewis.de>
parents: 28909
diff changeset
1630 information might be incorrect if the user has misconfigured the
bf1634b023d5 Patch #612627: Add encoding attribute to file objects, and determine
Martin v. Löwis <martin@v.loewis.de>
parents: 28909
diff changeset
1631 terminal). The attribute is read-only and may not be present on
bf1634b023d5 Patch #612627: Add encoding attribute to file objects, and determine
Martin v. Löwis <martin@v.loewis.de>
parents: 28909
diff changeset
1632 all file-like objects. It may also be \code{None}, in which case
bf1634b023d5 Patch #612627: Add encoding attribute to file objects, and determine
Martin v. Löwis <martin@v.loewis.de>
parents: 28909
diff changeset
1633 the file uses the system default encoding for converting Unicode
bf1634b023d5 Patch #612627: Add encoding attribute to file objects, and determine
Martin v. Löwis <martin@v.loewis.de>
parents: 28909
diff changeset
1634 strings.
bf1634b023d5 Patch #612627: Add encoding attribute to file objects, and determine
Martin v. Löwis <martin@v.loewis.de>
parents: 28909
diff changeset
1635
bf1634b023d5 Patch #612627: Add encoding attribute to file objects, and determine
Martin v. Löwis <martin@v.loewis.de>
parents: 28909
diff changeset
1636 \versionadded{2.3}
bf1634b023d5 Patch #612627: Add encoding attribute to file objects, and determine
Martin v. Löwis <martin@v.loewis.de>
parents: 28909
diff changeset
1637 \end{memberdesc}
bf1634b023d5 Patch #612627: Add encoding attribute to file objects, and determine
Martin v. Löwis <martin@v.loewis.de>
parents: 28909
diff changeset
1638
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1639 \begin{memberdesc}[file]{mode}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1640 The I/O mode for the file. If the file was created using the
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1641 \function{open()} built-in function, this will be the value of the
14685
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1642 \var{mode} parameter. This is a read-only attribute and may not be
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1643 present on all file-like objects.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1644 \end{memberdesc}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1645
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1646 \begin{memberdesc}[file]{name}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1647 If the file object was created using \function{open()}, the name of
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1648 the file. Otherwise, some string that indicates the source of the
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1649 file object, of the form \samp{<\mbox{\ldots}>}. This is a read-only
14685
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1650 attribute and may not be present on all file-like objects.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1651 \end{memberdesc}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1652
28171
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1653 \begin{memberdesc}[file]{newlines}
31282
8b62f4194a7e markup fix
Fred Drake <fdrake@acm.org>
parents: 31210
diff changeset
1654 If Python was built with the \longprogramopt{with-universal-newlines}
8b62f4194a7e markup fix
Fred Drake <fdrake@acm.org>
parents: 31210
diff changeset
1655 option to \program{configure} (the default) this read-only attribute
8b62f4194a7e markup fix
Fred Drake <fdrake@acm.org>
parents: 31210
diff changeset
1656 exists, and for files opened in
28171
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1657 universal newline read mode it keeps track of the types of newlines
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1658 encountered while reading the file. The values it can take are
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1659 \code{'\e r'}, \code{'\e n'}, \code{'\e r\e n'}, \code{None} (unknown,
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1660 no newlines read yet) or a tuple containing all the newline
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1661 types seen, to indicate that multiple
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1662 newline conventions were encountered. For files not opened in universal
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1663 newline read mode the value of this attribute will be \code{None}.
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1664 \end{memberdesc}
24fe023901b0 Back in June in revision 1.98 Steve (accidentally, presumably) wiped
Michael W. Hudson <mwh@python.net>
parents: 27919
diff changeset
1665
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1666 \begin{memberdesc}[file]{softspace}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1667 Boolean that indicates whether a space character needs to be printed
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1668 before another value when using the \keyword{print} statement.
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1669 Classes that are trying to simulate a file object should also have a
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1670 writable \member{softspace} attribute, which should be initialized to
14485
ac0246586d52 Improve a couple of references to the language reference, making them
Fred Drake <fdrake@acm.org>
parents: 14044
diff changeset
1671 zero. This will be automatic for most classes implemented in Python
ac0246586d52 Improve a couple of references to the language reference, making them
Fred Drake <fdrake@acm.org>
parents: 14044
diff changeset
1672 (care may be needed for objects that override attribute access); types
ac0246586d52 Improve a couple of references to the language reference, making them
Fred Drake <fdrake@acm.org>
parents: 14044
diff changeset
1673 implemented in C will have to provide a writable
ac0246586d52 Improve a couple of references to the language reference, making them
Fred Drake <fdrake@acm.org>
parents: 14044
diff changeset
1674 \member{softspace} attribute.
20580
376ee174ecd0 Use the \note and \warning macros where appropriate.
Fred Drake <fdrake@acm.org>
parents: 20173
diff changeset
1675 \note{This attribute is not used to control the
14705
4712f5b8f279 Clarify that the softspace attribute is used by print for state management,
Fred Drake <fdrake@acm.org>
parents: 14685
diff changeset
1676 \keyword{print} statement, but to allow the implementation of
20580
376ee174ecd0 Use the \note and \warning macros where appropriate.
Fred Drake <fdrake@acm.org>
parents: 20173
diff changeset
1677 \keyword{print} to keep track of its internal state.}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1678 \end{memberdesc}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1679
15383
eeb7c8a5b79f Document the proper exception to be raised by I/O operations on closed
Fred Drake <fdrake@acm.org>
parents: 15332
diff changeset
1680
20767
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1681 \subsection{Other Built-in Types \label{typesother}}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1682
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1683 The interpreter supports several other kinds of objects.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1684 Most of these support only one or two operations.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1685
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1686
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1687 \subsubsection{Modules \label{typesmodules}}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1688
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1689 The only special operation on a module is attribute access:
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1690 \code{\var{m}.\var{name}}, where \var{m} is a module and \var{name}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1691 accesses a name defined in \var{m}'s symbol table. Module attributes
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1692 can be assigned to. (Note that the \keyword{import} statement is not,
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1693 strictly speaking, an operation on a module object; \code{import
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1694 \var{foo}} does not require a module object named \var{foo} to exist,
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1695 rather it requires an (external) \emph{definition} for a module named
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1696 \var{foo} somewhere.)
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1697
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1698 A special member of every module is \member{__dict__}.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1699 This is the dictionary containing the module's symbol table.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1700 Modifying this dictionary will actually change the module's symbol
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1701 table, but direct assignment to the \member{__dict__} attribute is not
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1702 possible (you can write \code{\var{m}.__dict__['a'] = 1}, which
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1703 defines \code{\var{m}.a} to be \code{1}, but you can't write
31286
3894654b4848 fix a variety of markup bugs
Fred Drake <fdrake@acm.org>
parents: 31282
diff changeset
1704 \code{\var{m}.__dict__ = \{\}}). Modifying \member{__dict__} directly
3894654b4848 fix a variety of markup bugs
Fred Drake <fdrake@acm.org>
parents: 31282
diff changeset
1705 is not recommended.
20767
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1706
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1707 Modules built into the interpreter are written like this:
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1708 \code{<module 'sys' (built-in)>}. If loaded from a file, they are
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1709 written as \code{<module 'os' from
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1710 '/usr/local/lib/python\shortversion/os.pyc'>}.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1711
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1712
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1713 \subsubsection{Classes and Class Instances \label{typesobjects}}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1714 \nodename{Classes and Instances}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1715
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1716 See chapters 3 and 7 of the \citetitle[../ref/ref.html]{Python
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1717 Reference Manual} for these.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1718
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1719
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1720 \subsubsection{Functions \label{typesfunctions}}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1721
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1722 Function objects are created by function definitions. The only
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1723 operation on a function object is to call it:
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1724 \code{\var{func}(\var{argument-list})}.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1725
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1726 There are really two flavors of function objects: built-in functions
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1727 and user-defined functions. Both support the same operation (to call
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1728 the function), but the implementation is different, hence the
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1729 different object types.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1730
33102
f27935b46985 This is my patch
Michael W. Hudson <mwh@python.net>
parents: 33003
diff changeset
1731 See the \citetitle[../ref/ref.html]{Python Reference Manual} for more
f27935b46985 This is my patch
Michael W. Hudson <mwh@python.net>
parents: 33003
diff changeset
1732 information.
20767
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1733
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1734 \subsubsection{Methods \label{typesmethods}}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1735 \obindex{method}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1736
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1737 Methods are functions that are called using the attribute notation.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1738 There are two flavors: built-in methods (such as \method{append()} on
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1739 lists) and class instance methods. Built-in methods are described
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1740 with the types that support them.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1741
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1742 The implementation adds two special read-only attributes to class
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1743 instance methods: \code{\var{m}.im_self} is the object on which the
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1744 method operates, and \code{\var{m}.im_func} is the function
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1745 implementing the method. Calling \code{\var{m}(\var{arg-1},
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1746 \var{arg-2}, \textrm{\ldots}, \var{arg-n})} is completely equivalent to
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1747 calling \code{\var{m}.im_func(\var{m}.im_self, \var{arg-1},
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1748 \var{arg-2}, \textrm{\ldots}, \var{arg-n})}.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1749
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1750 Class instance methods are either \emph{bound} or \emph{unbound},
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1751 referring to whether the method was accessed through an instance or a
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1752 class, respectively. When a method is unbound, its \code{im_self}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1753 attribute will be \code{None} and if called, an explicit \code{self}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1754 object must be passed as the first argument. In this case,
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1755 \code{self} must be an instance of the unbound method's class (or a
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1756 subclass of that class), otherwise a \code{TypeError} is raised.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1757
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1758 Like function objects, methods objects support getting
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1759 arbitrary attributes. However, since method attributes are actually
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1760 stored on the underlying function object (\code{meth.im_func}),
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1761 setting method attributes on either bound or unbound methods is
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1762 disallowed. Attempting to set a method attribute results in a
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1763 \code{TypeError} being raised. In order to set a method attribute,
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1764 you need to explicitly set it on the underlying function object:
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1765
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1766 \begin{verbatim}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1767 class C:
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1768 def method(self):
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1769 pass
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1770
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1771 c = C()
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1772 c.method.im_func.whoami = 'my name is c'
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1773 \end{verbatim}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1774
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1775 See the \citetitle[../ref/ref.html]{Python Reference Manual} for more
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1776 information.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1777
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1778
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1779 \subsubsection{Code Objects \label{bltin-code-objects}}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1780 \obindex{code}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1781
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1782 Code objects are used by the implementation to represent
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1783 ``pseudo-compiled'' executable Python code such as a function body.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1784 They differ from function objects because they don't contain a
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1785 reference to their global execution environment. Code objects are
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1786 returned by the built-in \function{compile()} function and can be
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1787 extracted from function objects through their \member{func_code}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1788 attribute.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1789 \bifuncindex{compile}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1790 \withsubitem{(function object attribute)}{\ttindex{func_code}}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1791
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1792 A code object can be executed or evaluated by passing it (instead of a
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1793 source string) to the \keyword{exec} statement or the built-in
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1794 \function{eval()} function.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1795 \stindex{exec}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1796 \bifuncindex{eval}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1797
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1798 See the \citetitle[../ref/ref.html]{Python Reference Manual} for more
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1799 information.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1800
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1801
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1802 \subsubsection{Type Objects \label{bltin-type-objects}}
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Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1803
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Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1804 Type objects represent the various object types. An object's type is
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1805 accessed by the built-in function \function{type()}. There are no special
31286
3894654b4848 fix a variety of markup bugs
Fred Drake <fdrake@acm.org>
parents: 31282
diff changeset
1806 operations on types. The standard module \refmodule{types} defines names
20767
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Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1807 for all standard built-in types.
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Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1808 \bifuncindex{type}
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Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1809 \refstmodindex{types}
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Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1810
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Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1811 Types are written like this: \code{<type 'int'>}.
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Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1812
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Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1813
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Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1814 \subsubsection{The Null Object \label{bltin-null-object}}
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Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1815
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Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1816 This object is returned by functions that don't explicitly return a
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1817 value. It supports no special operations. There is exactly one null
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Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1818 object, named \code{None} (a built-in name).
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Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1819
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Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1820 It is written as \code{None}.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1821
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Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1822
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Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1823 \subsubsection{The Ellipsis Object \label{bltin-ellipsis-object}}
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Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1824
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Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1825 This object is used by extended slice notation (see the
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Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1826 \citetitle[../ref/ref.html]{Python Reference Manual}). It supports no
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1827 special operations. There is exactly one ellipsis object, named
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1828 \constant{Ellipsis} (a built-in name).
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Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1829
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Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1830 It is written as \code{Ellipsis}.
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Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1831
22785
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
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diff changeset
1832 \subsubsection{Boolean Values}
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
1833
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
1834 Boolean values are the two constant objects \code{False} and
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
1835 \code{True}. They are used to represent truth values (although other
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
1836 values can also be considered false or true). In numeric contexts
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
1837 (for example when used as the argument to an arithmetic operator),
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
1838 they behave like the integers 0 and 1, respectively. The built-in
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
1839 function \function{bool()} can be used to cast any value to a Boolean,
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
1840 if the value can be interpreted as a truth value (see section Truth
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
1841 Value Testing above).
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
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parents: 22241
diff changeset
1842
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
1843 They are written as \code{False} and \code{True}, respectively.
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
1844 \index{False}
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diff changeset
1845 \index{True}
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parents: 22241
diff changeset
1846 \indexii{Boolean}{values}
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
1847
20767
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diff changeset
1848
10156
0f7d694bc334 Make sure all HTML pages generated from this section have reasonable
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diff changeset
1849 \subsubsection{Internal Objects \label{typesinternal}}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
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diff changeset
1850
11463
17e12305973e Use \citetitle and \programopt as appropriate.
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diff changeset
1851 See the \citetitle[../ref/ref.html]{Python Reference Manual} for this
14044
a905c5aa0691 As pointed out by Denis S. Otkidach <den@analyt.chem.msu.ru>, xrange()
Fred Drake <fdrake@acm.org>
parents: 13967
diff changeset
1852 information. It describes stack frame objects, traceback objects, and
a905c5aa0691 As pointed out by Denis S. Otkidach <den@analyt.chem.msu.ru>, xrange()
Fred Drake <fdrake@acm.org>
parents: 13967
diff changeset
1853 slice objects.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
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parents:
diff changeset
1854
8a306dfd9f33 Move files around to get the names to match the module names except for
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diff changeset
1855
9083
bc41e86c938c Markup nits.
Fred Drake <fdrake@acm.org>
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diff changeset
1856 \subsection{Special Attributes \label{specialattrs}}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
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diff changeset
1857
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diff changeset
1858 The implementation adds a few special read-only attributes to several
32070
b319db3869d8 add note about the __name__ read-only attribute
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diff changeset
1859 object types, where they are relevant. Some of these are not reported
b319db3869d8 add note about the __name__ read-only attribute
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diff changeset
1860 by the \function{dir()} built-in function.
8730
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diff changeset
1861
15383
eeb7c8a5b79f Document the proper exception to be raised by I/O operations on closed
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diff changeset
1862 \begin{memberdesc}[object]{__dict__}
eeb7c8a5b79f Document the proper exception to be raised by I/O operations on closed
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diff changeset
1863 A dictionary or other mapping object used to store an
9083
bc41e86c938c Markup nits.
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diff changeset
1864 object's (writable) attributes.
15383
eeb7c8a5b79f Document the proper exception to be raised by I/O operations on closed
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diff changeset
1865 \end{memberdesc}
8730
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diff changeset
1866
15383
eeb7c8a5b79f Document the proper exception to be raised by I/O operations on closed
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diff changeset
1867 \begin{memberdesc}[object]{__methods__}
21159
6fa96b329e15 Remove most references to __members__ and __methods__, leaving only one pair
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diff changeset
1868 \deprecated{2.2}{Use the built-in function \function{dir()} to get a
6fa96b329e15 Remove most references to __members__ and __methods__, leaving only one pair
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diff changeset
1869 list of an object's attributes. This attribute is no longer available.}
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diff changeset
1870 \end{memberdesc}
8730
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diff changeset
1871
15383
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diff changeset
1872 \begin{memberdesc}[object]{__members__}
21159
6fa96b329e15 Remove most references to __members__ and __methods__, leaving only one pair
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diff changeset
1873 \deprecated{2.2}{Use the built-in function \function{dir()} to get a
6fa96b329e15 Remove most references to __members__ and __methods__, leaving only one pair
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diff changeset
1874 list of an object's attributes. This attribute is no longer available.}
15383
eeb7c8a5b79f Document the proper exception to be raised by I/O operations on closed
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diff changeset
1875 \end{memberdesc}
8730
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diff changeset
1876
15383
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diff changeset
1877 \begin{memberdesc}[instance]{__class__}
eeb7c8a5b79f Document the proper exception to be raised by I/O operations on closed
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parents: 15332
diff changeset
1878 The class to which a class instance belongs.
eeb7c8a5b79f Document the proper exception to be raised by I/O operations on closed
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diff changeset
1879 \end{memberdesc}
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diff changeset
1880
eeb7c8a5b79f Document the proper exception to be raised by I/O operations on closed
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diff changeset
1881 \begin{memberdesc}[class]{__bases__}
18416
33b4357aebb8 Fix up a few style nits -- avoid "e.g." and "i.e." -- these make
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diff changeset
1882 The tuple of base classes of a class object. If there are no base
33b4357aebb8 Fix up a few style nits -- avoid "e.g." and "i.e." -- these make
Fred Drake <fdrake@acm.org>
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diff changeset
1883 classes, this will be an empty tuple.
15383
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diff changeset
1884 \end{memberdesc}
32070
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diff changeset
1885
b319db3869d8 add note about the __name__ read-only attribute
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diff changeset
1886 \begin{memberdesc}[class]{__name__}
b319db3869d8 add note about the __name__ read-only attribute
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diff changeset
1887 The name of the class or type.
b319db3869d8 add note about the __name__ read-only attribute
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diff changeset
1888 \end{memberdesc}