Mercurial > cpython-lru_cache-weakref
annotate Doc/lib/libstdtypes.tex @ 27998:e27f58a50737 legacy-trunk
SF bug #690377: Dud footnote reference in distutils docs
| author | Raymond Hettinger <python@rcn.com> |
|---|---|
| date | Fri, 21 Feb 2003 02:47:09 +0000 |
| parents | 4b5c2e025c5e |
| children | 24fe023901b0 |
| rev | line source |
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| 9083 | 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 all objects can be compared, tested for truth value, and converted to |
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17 a string (with the \code{`\textrm{\ldots}`} notation). The latter |
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18 conversion is implicitly used when an object is written by the |
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19 \keyword{print}\stindex{print} statement. |
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20 |
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21 |
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22 \subsection{Truth Value Testing} \label{truth} |
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23 |
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24 Any object can be tested for truth value, for use in an \keyword{if} or |
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25 \keyword{while} condition or as operand of the Boolean operations below. |
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26 The following values are considered false: |
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27 \stindex{if} |
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28 \stindex{while} |
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29 \indexii{truth}{value} |
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30 \indexii{Boolean}{operations} |
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31 \index{false} |
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32 |
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33 \begin{itemize} |
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34 |
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35 \item \code{None} |
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36 \withsubitem{(Built-in object)}{\ttindex{None}} |
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37 |
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38 \item \code{False} |
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39 \withsubitem{(Built-in object)}{\ttindex{False}} |
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40 |
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41 \item zero of any numeric type, for example, \code{0}, \code{0L}, |
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42 \code{0.0}, \code{0j}. |
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43 |
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44 \item any empty sequence, for example, \code{''}, \code{()}, \code{[]}. |
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45 |
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46 \item any empty mapping, for example, \code{\{\}}. |
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47 |
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48 \item instances of user-defined classes, if the class defines a |
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49 \method{__nonzero__()} or \method{__len__()} method, when that |
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50 method returns the integer zero or \class{bool} value |
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51 \code{False}.\footnote{Additional |
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52 information on these special methods may be found in the |
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53 \citetitle[../ref/ref.html]{Python Reference Manual}.} |
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54 |
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55 \end{itemize} |
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56 |
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57 All other values are considered true --- so objects of many types are |
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58 always true. |
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59 \index{true} |
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60 |
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61 Operations and built-in functions that have a Boolean result always |
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62 return \code{0} or \code{False} for false and \code{1} or \code{True} |
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63 for true, unless otherwise stated. (Important exception: the Boolean |
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64 operations \samp{or}\opindex{or} and \samp{and}\opindex{and} always |
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65 return one of their operands.) |
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66 \index{False} |
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67 \index{True} |
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68 |
| 9083 | 69 \subsection{Boolean Operations \label{boolean}} |
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70 |
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71 These are the Boolean operations, ordered by ascending priority: |
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72 \indexii{Boolean}{operations} |
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73 |
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74 \begin{tableiii}{c|l|c}{code}{Operation}{Result}{Notes} |
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75 \lineiii{\var{x} or \var{y}} |
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76 {if \var{x} is false, then \var{y}, else \var{x}}{(1)} |
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77 \lineiii{\var{x} and \var{y}} |
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78 {if \var{x} is false, then \var{x}, else \var{y}}{(1)} |
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79 \hline |
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80 \lineiii{not \var{x}} |
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81 {if \var{x} is false, then \code{True}, else \code{False}}{(2)} |
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82 \end{tableiii} |
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83 \opindex{and} |
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84 \opindex{or} |
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85 \opindex{not} |
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86 |
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87 \noindent |
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88 Notes: |
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89 |
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90 \begin{description} |
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91 |
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92 \item[(1)] |
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93 These only evaluate their second argument if needed for their outcome. |
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94 |
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95 \item[(2)] |
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96 \samp{not} has a lower priority than non-Boolean operators, so |
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97 \code{not \var{a} == \var{b}} is interpreted as \code{not (\var{a} == |
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98 \var{b})}, and \code{\var{a} == not \var{b}} is a syntax error. |
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99 |
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100 \end{description} |
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101 |
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102 |
| 9083 | 103 \subsection{Comparisons \label{comparisons}} |
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104 |
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105 Comparison operations are supported by all objects. They all have the |
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106 same priority (which is higher than that of the Boolean operations). |
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107 Comparisons can be chained arbitrarily; for example, \code{\var{x} < |
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108 \var{y} <= \var{z}} is equivalent to \code{\var{x} < \var{y} and |
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109 \var{y} <= \var{z}}, except that \var{y} is evaluated only once (but |
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110 in both cases \var{z} is not evaluated at all when \code{\var{x} < |
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111 \var{y}} is found to be false). |
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112 \indexii{chaining}{comparisons} |
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113 |
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114 This table summarizes the comparison operations: |
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115 |
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116 \begin{tableiii}{c|l|c}{code}{Operation}{Meaning}{Notes} |
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117 \lineiii{<}{strictly less than}{} |
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118 \lineiii{<=}{less than or equal}{} |
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119 \lineiii{>}{strictly greater than}{} |
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120 \lineiii{>=}{greater than or equal}{} |
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121 \lineiii{==}{equal}{} |
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122 \lineiii{!=}{not equal}{(1)} |
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123 \lineiii{<>}{not equal}{(1)} |
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124 \lineiii{is}{object identity}{} |
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125 \lineiii{is not}{negated object identity}{} |
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126 \end{tableiii} |
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127 \indexii{operator}{comparison} |
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128 \opindex{==} % XXX *All* others have funny characters < ! > |
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129 \opindex{is} |
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130 \opindex{is not} |
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131 |
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132 \noindent |
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133 Notes: |
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134 |
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135 \begin{description} |
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136 |
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137 \item[(1)] |
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138 \code{<>} and \code{!=} are alternate spellings for the same operator. |
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139 \code{!=} is the preferred spelling; \code{<>} is obsolescent. |
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140 |
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141 \end{description} |
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142 |
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143 Objects of different types, except different numeric types, never |
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144 compare equal; such objects are ordered consistently but arbitrarily |
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145 (so that sorting a heterogeneous array yields a consistent result). |
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146 Furthermore, some types (for example, file objects) support only a |
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147 degenerate notion of comparison where any two objects of that type are |
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148 unequal. Again, such objects are ordered arbitrarily but |
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149 consistently. The \code{<}, \code{<=}, \code{>} and \code{>=} |
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150 operators will raise a \exception{TypeError} exception when any operand |
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151 is a complex number. |
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152 \indexii{object}{numeric} |
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153 \indexii{objects}{comparing} |
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154 |
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155 Instances of a class normally compare as non-equal unless the class |
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156 \withsubitem{(instance method)}{\ttindex{__cmp__()}} |
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157 defines the \method{__cmp__()} method. Refer to the |
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158 \citetitle[../ref/customization.html]{Python Reference Manual} for |
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159 information on the use of this method to effect object comparisons. |
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160 |
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161 \strong{Implementation note:} Objects of different types except |
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162 numbers are ordered by their type names; objects of the same types |
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163 that don't support proper comparison are ordered by their address. |
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164 |
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165 Two more operations with the same syntactic priority, |
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166 \samp{in}\opindex{in} and \samp{not in}\opindex{not in}, are supported |
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167 only by sequence types (below). |
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168 |
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169 |
| 9083 | 170 \subsection{Numeric Types \label{typesnumeric}} |
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171 |
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172 There are four distinct numeric types: \dfn{plain integers}, |
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173 \dfn{long integers}, |
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174 \dfn{floating point numbers}, and \dfn{complex numbers}. |
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175 In addition, Booleans are a subtype of plain integers. |
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176 Plain integers (also just called \dfn{integers}) |
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177 are implemented using \ctype{long} in C, which gives them at least 32 |
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178 bits of precision. Long integers have unlimited precision. Floating |
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179 point numbers are implemented using \ctype{double} in C. All bets on |
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180 their precision are off unless you happen to know the machine you are |
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181 working with. |
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182 \obindex{numeric} |
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183 \obindex{Boolean} |
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184 \obindex{integer} |
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185 \obindex{long integer} |
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186 \obindex{floating point} |
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187 \obindex{complex number} |
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188 \indexii{C}{language} |
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189 |
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190 Complex numbers have a real and imaginary part, which are each |
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191 implemented using \ctype{double} in C. To extract these parts from |
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192 a complex number \var{z}, use \code{\var{z}.real} and \code{\var{z}.imag}. |
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193 |
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194 Numbers are created by numeric literals or as the result of built-in |
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195 functions and operators. Unadorned integer literals (including hex |
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196 and octal numbers) yield plain integers unless the value they denote |
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197 is too large to be represented as a plain integer, in which case |
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198 they yield a long integer. Integer literals with an |
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199 \character{L} or \character{l} suffix yield long integers |
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200 (\character{L} is preferred because \samp{1l} looks too much like |
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201 eleven!). Numeric literals containing a decimal point or an exponent |
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202 sign yield floating point numbers. Appending \character{j} or |
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203 \character{J} to a numeric literal yields a complex number with a |
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204 zero real part. A complex numeric literal is the sum of a real and |
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205 an imaginary part. |
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206 \indexii{numeric}{literals} |
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207 \indexii{integer}{literals} |
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208 \indexiii{long}{integer}{literals} |
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209 \indexii{floating point}{literals} |
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210 \indexii{complex number}{literals} |
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211 \indexii{hexadecimal}{literals} |
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212 \indexii{octal}{literals} |
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213 |
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214 Python fully supports mixed arithmetic: when a binary arithmetic |
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215 operator has operands of different numeric types, the operand with the |
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216 ``narrower'' type is widened to that of the other, where plain |
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217 integer is narrower than long integer is narrower than floating point is |
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218 narrower than complex. |
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219 Comparisons between numbers of mixed type use the same rule.\footnote{ |
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220 As a consequence, the list \code{[1, 2]} is considered equal |
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221 to \code{[1.0, 2.0]}, and similarly for tuples. |
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222 } The constructors \function{int()}, \function{long()}, \function{float()}, |
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223 and \function{complex()} can be used |
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224 to produce numbers of a specific type. |
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225 \index{arithmetic} |
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226 \bifuncindex{int} |
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227 \bifuncindex{long} |
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228 \bifuncindex{float} |
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229 \bifuncindex{complex} |
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230 |
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231 All numeric types support the following operations, sorted by |
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232 ascending priority (operations in the same box have the same |
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233 priority; all numeric operations have a higher priority than |
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234 comparison operations): |
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235 |
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236 \begin{tableiii}{c|l|c}{code}{Operation}{Result}{Notes} |
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237 \lineiii{\var{x} + \var{y}}{sum of \var{x} and \var{y}}{} |
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238 \lineiii{\var{x} - \var{y}}{difference of \var{x} and \var{y}}{} |
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239 \hline |
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240 \lineiii{\var{x} * \var{y}}{product of \var{x} and \var{y}}{} |
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241 \lineiii{\var{x} / \var{y}}{quotient of \var{x} and \var{y}}{(1)} |
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242 \lineiii{\var{x} \%{} \var{y}}{remainder of \code{\var{x} / \var{y}}}{} |
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243 \hline |
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244 \lineiii{-\var{x}}{\var{x} negated}{} |
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245 \lineiii{+\var{x}}{\var{x} unchanged}{} |
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246 \hline |
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247 \lineiii{abs(\var{x})}{absolute value or magnitude of \var{x}}{} |
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248 \lineiii{int(\var{x})}{\var{x} converted to integer}{(2)} |
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249 \lineiii{long(\var{x})}{\var{x} converted to long integer}{(2)} |
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250 \lineiii{float(\var{x})}{\var{x} converted to floating point}{} |
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251 \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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252 \lineiii{\var{c}.conjugate()}{conjugate of the complex number \var{c}}{} |
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253 \lineiii{divmod(\var{x}, \var{y})}{the pair \code{(\var{x} / \var{y}, \var{x} \%{} \var{y})}}{(3)} |
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254 \lineiii{pow(\var{x}, \var{y})}{\var{x} to the power \var{y}}{} |
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255 \lineiii{\var{x} ** \var{y}}{\var{x} to the power \var{y}}{} |
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256 \end{tableiii} |
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257 \indexiii{operations on}{numeric}{types} |
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258 \withsubitem{(complex number method)}{\ttindex{conjugate()}} |
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259 |
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260 \noindent |
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261 Notes: |
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262 \begin{description} |
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263 |
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264 \item[(1)] |
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265 For (plain or long) integer division, the result is an integer. |
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266 The result is always rounded towards minus infinity: 1/2 is 0, |
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267 (-1)/2 is -1, 1/(-2) is -1, and (-1)/(-2) is 0. Note that the result |
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268 is a long integer if either operand is a long integer, regardless of |
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269 the numeric value. |
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270 \indexii{integer}{division} |
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271 \indexiii{long}{integer}{division} |
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272 |
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273 \item[(2)] |
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274 Conversion from floating point to (long or plain) integer may round or |
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275 truncate as in C; see functions \function{floor()} and |
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276 \function{ceil()} in the \refmodule{math}\refbimodindex{math} module |
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277 for well-defined conversions. |
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278 \withsubitem{(in module math)}{\ttindex{floor()}\ttindex{ceil()}} |
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279 \indexii{numeric}{conversions} |
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280 \indexii{C}{language} |
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281 |
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282 \item[(3)] |
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283 See section \ref{built-in-funcs}, ``Built-in Functions,'' for a full |
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284 description. |
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285 |
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286 \end{description} |
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287 % XXXJH exceptions: overflow (when? what operations?) zerodivision |
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288 |
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289 \subsubsection{Bit-string Operations on Integer Types \label{bitstring-ops}} |
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290 \nodename{Bit-string Operations} |
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291 |
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292 Plain and long integer types support additional operations that make |
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293 sense only for bit-strings. Negative numbers are treated as their 2's |
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294 complement value (for long integers, this assumes a sufficiently large |
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295 number of bits that no overflow occurs during the operation). |
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296 |
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297 The priorities of the binary bit-wise operations are all lower than |
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298 the numeric operations and higher than the comparisons; the unary |
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299 operation \samp{\~} has the same priority as the other unary numeric |
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300 operations (\samp{+} and \samp{-}). |
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301 |
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302 This table lists the bit-string operations sorted in ascending |
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303 priority (operations in the same box have the same priority): |
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304 |
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305 \begin{tableiii}{c|l|c}{code}{Operation}{Result}{Notes} |
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306 \lineiii{\var{x} | \var{y}}{bitwise \dfn{or} of \var{x} and \var{y}}{} |
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307 \lineiii{\var{x} \^{} \var{y}}{bitwise \dfn{exclusive or} of \var{x} and \var{y}}{} |
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308 \lineiii{\var{x} \&{} \var{y}}{bitwise \dfn{and} of \var{x} and \var{y}}{} |
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309 \lineiii{\var{x} << \var{n}}{\var{x} shifted left by \var{n} bits}{(1), (2)} |
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310 \lineiii{\var{x} >> \var{n}}{\var{x} shifted right by \var{n} bits}{(1), (3)} |
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311 \hline |
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312 \lineiii{\~\var{x}}{the bits of \var{x} inverted}{} |
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313 \end{tableiii} |
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314 \indexiii{operations on}{integer}{types} |
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315 \indexii{bit-string}{operations} |
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316 \indexii{shifting}{operations} |
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317 \indexii{masking}{operations} |
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318 |
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319 \noindent |
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320 Notes: |
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321 \begin{description} |
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322 \item[(1)] Negative shift counts are illegal and cause a |
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323 \exception{ValueError} to be raised. |
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324 \item[(2)] A left shift by \var{n} bits is equivalent to |
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325 multiplication by \code{pow(2, \var{n})} without overflow check. |
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326 \item[(3)] A right shift by \var{n} bits is equivalent to |
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327 division by \code{pow(2, \var{n})} without overflow check. |
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328 \end{description} |
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329 |
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330 |
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331 \subsection{Iterator Types \label{typeiter}} |
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332 |
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333 \versionadded{2.2} |
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334 \index{iterator protocol} |
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335 \index{protocol!iterator} |
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336 \index{sequence!iteration} |
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337 \index{container!iteration over} |
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338 |
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339 Python supports a concept of iteration over containers. This is |
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340 implemented using two distinct methods; these are used to allow |
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341 user-defined classes to support iteration. Sequences, described below |
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342 in more detail, always support the iteration methods. |
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343 |
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344 One method needs to be defined for container objects to provide |
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345 iteration support: |
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346 |
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347 \begin{methoddesc}[container]{__iter__}{} |
| 18839 | 348 Return an iterator object. The object is required to support the |
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349 iterator protocol described below. If a container supports |
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350 different types of iteration, additional methods can be provided to |
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351 specifically request iterators for those iteration types. (An |
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352 example of an object supporting multiple forms of iteration would be |
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353 a tree structure which supports both breadth-first and depth-first |
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354 traversal.) This method corresponds to the \member{tp_iter} slot of |
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355 the type structure for Python objects in the Python/C API. |
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356 \end{methoddesc} |
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357 |
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358 The iterator objects themselves are required to support the following |
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359 two methods, which together form the \dfn{iterator protocol}: |
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360 |
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361 \begin{methoddesc}[iterator]{__iter__}{} |
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362 Return the iterator object itself. This is required to allow both |
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363 containers and iterators to be used with the \keyword{for} and |
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364 \keyword{in} statements. This method corresponds to the |
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365 \member{tp_iter} slot of the type structure for Python objects in |
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366 the Python/C API. |
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367 \end{methoddesc} |
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368 |
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369 \begin{methoddesc}[iterator]{next}{} |
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370 Return the next item from the container. If there are no further |
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371 items, raise the \exception{StopIteration} exception. This method |
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372 corresponds to the \member{tp_iternext} slot of the type structure |
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373 for Python objects in the Python/C API. |
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374 \end{methoddesc} |
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375 |
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376 Python defines several iterator objects to support iteration over |
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377 general and specific sequence types, dictionaries, and other more |
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378 specialized forms. The specific types are not important beyond their |
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379 implementation of the iterator protocol. |
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380 |
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381 The intention of the protocol is that once an iterator's |
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382 \method{next()} method raises \exception{StopIteration}, it will |
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383 continue to do so on subsequent calls. Implementations that |
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384 do not obey this property are deemed broken. (This constraint |
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385 was added in Python 2.3; in Python 2.2, various iterators are |
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386 broken according to this rule.) |
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387 |
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388 |
| 9083 | 389 \subsection{Sequence Types \label{typesseq}} |
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390 |
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391 There are six sequence types: strings, Unicode strings, lists, |
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392 tuples, buffers, and xrange objects. |
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393 |
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394 String literals are written in single or double quotes: |
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395 \code{'xyzzy'}, \code{"frobozz"}. See chapter 2 of the |
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396 \citetitle[../ref/strings.html]{Python Reference Manual} for more about |
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397 string literals. Unicode strings are much like strings, but are |
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398 specified in the syntax using a preceeding \character{u} character: |
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399 \code{u'abc'}, \code{u"def"}. Lists are constructed with square brackets, |
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400 separating items with commas: \code{[a, b, c]}. Tuples are |
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401 constructed by the comma operator (not within square brackets), with |
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402 or without enclosing parentheses, but an empty tuple must have the |
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403 enclosing parentheses, e.g., \code{a, b, c} or \code{()}. A single |
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404 item tuple must have a trailing comma, e.g., \code{(d,)}. |
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405 \obindex{sequence} |
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406 \obindex{string} |
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407 \obindex{Unicode} |
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408 \obindex{tuple} |
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409 \obindex{list} |
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410 |
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411 Buffer objects are not directly supported by Python syntax, but can be |
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412 created by calling the builtin function |
| 25393 | 413 \function{buffer()}.\bifuncindex{buffer} They don't support |
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414 concatenation or repetition. |
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415 \obindex{buffer} |
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416 |
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417 Xrange objects are similar to buffers in that there is no specific |
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418 syntax to create them, but they are created using the \function{xrange()} |
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419 function.\bifuncindex{xrange} They don't support slicing, |
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420 concatenation or repetition, and using \code{in}, \code{not in}, |
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421 \function{min()} or \function{max()} on them is inefficient. |
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422 \obindex{xrange} |
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423 |
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424 Most sequence types support the following operations. The \samp{in} and |
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425 \samp{not in} operations have the same priorities as the comparison |
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426 operations. The \samp{+} and \samp{*} operations have the same |
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427 priority as the corresponding numeric operations.\footnote{They must |
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428 have since the parser can't tell the type of the operands.} |
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429 |
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430 This table lists the sequence operations sorted in ascending priority |
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431 (operations in the same box have the same priority). In the table, |
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432 \var{s} and \var{t} are sequences of the same type; \var{n}, \var{i} |
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433 and \var{j} are integers: |
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434 |
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435 \begin{tableiii}{c|l|c}{code}{Operation}{Result}{Notes} |
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436 \lineiii{\var{x} in \var{s}}{\code{1} if an item of \var{s} is equal to \var{x}, else \code{0}}{(1)} |
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437 \lineiii{\var{x} not in \var{s}}{\code{0} if an item of \var{s} is |
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438 equal to \var{x}, else \code{1}}{(1)} |
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439 \hline |
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440 \lineiii{\var{s} + \var{t}}{the concatenation of \var{s} and \var{t}}{} |
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441 \lineiii{\var{s} * \var{n}\textrm{,} \var{n} * \var{s}}{\var{n} shallow copies of \var{s} concatenated}{(2)} |
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442 \hline |
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443 \lineiii{\var{s}[\var{i}]}{\var{i}'th item of \var{s}, origin 0}{(3)} |
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444 \lineiii{\var{s}[\var{i}:\var{j}]}{slice of \var{s} from \var{i} to \var{j}}{(3), (4)} |
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445 \hline |
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446 \lineiii{len(\var{s})}{length of \var{s}}{} |
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447 \lineiii{min(\var{s})}{smallest item of \var{s}}{} |
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448 \lineiii{max(\var{s})}{largest item of \var{s}}{} |
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449 \end{tableiii} |
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450 \indexiii{operations on}{sequence}{types} |
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451 \bifuncindex{len} |
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452 \bifuncindex{min} |
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453 \bifuncindex{max} |
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454 \indexii{concatenation}{operation} |
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455 \indexii{repetition}{operation} |
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456 \indexii{subscript}{operation} |
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457 \indexii{slice}{operation} |
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458 \opindex{in} |
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459 \opindex{not in} |
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460 |
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461 \noindent |
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462 Notes: |
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463 |
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464 \begin{description} |
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465 \item[(1)] When \var{s} is a string or Unicode string object the |
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466 \code{in} and \code{not in} operations act like a substring test. In |
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467 Python versions before 2.3, \var{x} had to be a string of length 1. |
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468 In Python 2.3 and beyond, \var{x} may be a string of any length. |
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469 |
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470 \item[(2)] Values of \var{n} less than \code{0} are treated as |
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471 \code{0} (which yields an empty sequence of the same type as |
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472 \var{s}). Note also that the copies are shallow; nested structures |
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473 are not copied. This often haunts new Python programmers; consider: |
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474 |
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475 \begin{verbatim} |
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476 >>> lists = [[]] * 3 |
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477 >>> lists |
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478 [[], [], []] |
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479 >>> lists[0].append(3) |
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480 >>> lists |
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481 [[3], [3], [3]] |
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482 \end{verbatim} |
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483 |
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484 What has happened is that \code{lists} is a list containing three |
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485 copies of the list \code{[[]]} (a one-element list containing an |
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486 empty list), but the contained list is shared by each copy. You can |
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487 create a list of different lists this way: |
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488 |
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489 \begin{verbatim} |
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490 >>> lists = [[] for i in range(3)] |
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491 >>> lists[0].append(3) |
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492 >>> lists[1].append(5) |
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493 >>> lists[2].append(7) |
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494 >>> lists |
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495 [[3], [5], [7]] |
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496 \end{verbatim} |
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497 |
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498 \item[(3)] If \var{i} or \var{j} is negative, the index is relative to |
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499 the end of the string: \code{len(\var{s}) + \var{i}} or |
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500 \code{len(\var{s}) + \var{j}} is substituted. But note that \code{-0} is |
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501 still \code{0}. |
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502 |
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503 \item[(4)] The slice of \var{s} from \var{i} to \var{j} is defined as |
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504 the sequence of items with index \var{k} such that \code{\var{i} <= |
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505 \var{k} < \var{j}}. If \var{i} or \var{j} is greater than |
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506 \code{len(\var{s})}, use \code{len(\var{s})}. If \var{i} is omitted, |
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507 use \code{0}. If \var{j} is omitted, use \code{len(\var{s})}. If |
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508 \var{i} is greater than or equal to \var{j}, the slice is empty. |
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509 \end{description} |
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510 |
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511 |
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512 \subsubsection{String Methods \label{string-methods}} |
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513 |
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514 These are the string methods which both 8-bit strings and Unicode |
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515 objects support: |
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516 |
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517 \begin{methoddesc}[string]{capitalize}{} |
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518 Return a copy of the string with only its first character capitalized. |
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519 \end{methoddesc} |
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520 |
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521 \begin{methoddesc}[string]{center}{width} |
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522 Return centered in a string of length \var{width}. Padding is done |
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523 using spaces. |
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524 \end{methoddesc} |
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525 |
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526 \begin{methoddesc}[string]{count}{sub\optional{, start\optional{, end}}} |
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527 Return the number of occurrences of substring \var{sub} in string |
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528 S\code{[\var{start}:\var{end}]}. Optional arguments \var{start} and |
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529 \var{end} are interpreted as in slice notation. |
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530 \end{methoddesc} |
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531 |
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532 \begin{methoddesc}[string]{decode}{\optional{encoding\optional{, errors}}} |
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533 Decodes the string using the codec registered for \var{encoding}. |
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534 \var{encoding} defaults to the default string encoding. \var{errors} |
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535 may be given to set a different error handling scheme. The default is |
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536 \code{'strict'}, meaning that encoding errors raise |
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537 \exception{ValueError}. Other possible values are \code{'ignore'} and |
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538 \code{replace'}. |
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539 \versionadded{2.2} |
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540 \end{methoddesc} |
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541 |
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542 \begin{methoddesc}[string]{encode}{\optional{encoding\optional{,errors}}} |
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543 Return an encoded version of the string. Default encoding is the current |
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544 default string encoding. \var{errors} may be given to set a different |
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545 error handling scheme. The default for \var{errors} is |
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546 \code{'strict'}, meaning that encoding errors raise a |
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547 \exception{ValueError}. Other possible values are \code{'ignore'} and |
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548 \code{'replace'}. |
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549 \versionadded{2.0} |
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550 \end{methoddesc} |
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551 |
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552 \begin{methoddesc}[string]{endswith}{suffix\optional{, start\optional{, end}}} |
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553 Return true if the string ends with the specified \var{suffix}, |
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554 otherwise return false. With optional \var{start}, test beginning at |
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555 that position. With optional \var{end}, stop comparing at that position. |
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556 \end{methoddesc} |
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557 |
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558 \begin{methoddesc}[string]{expandtabs}{\optional{tabsize}} |
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559 Return a copy of the string where all tab characters are expanded |
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560 using spaces. If \var{tabsize} is not given, a tab size of \code{8} |
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561 characters is assumed. |
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562 \end{methoddesc} |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
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|
563 |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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diff
changeset
|
564 \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
|
565 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
|
566 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
|
567 \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
|
568 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
|
569 not found. |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents:
13894
diff
changeset
|
570 \end{methoddesc} |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents:
13894
diff
changeset
|
571 |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents:
13894
diff
changeset
|
572 \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
|
573 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:
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diff
changeset
|
574 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
|
575 \end{methoddesc} |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
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13894
diff
changeset
|
576 |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents:
13894
diff
changeset
|
577 \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
|
578 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:
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diff
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|
579 is at least one character, false otherwise. |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents:
13894
diff
changeset
|
580 \end{methoddesc} |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
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13894
diff
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|
581 |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents:
13894
diff
changeset
|
582 \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
|
583 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:
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diff
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|
584 is at least one character, false otherwise. |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents:
13894
diff
changeset
|
585 \end{methoddesc} |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents:
13894
diff
changeset
|
586 |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents:
13894
diff
changeset
|
587 \begin{methoddesc}[string]{isdigit}{} |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents:
13894
diff
changeset
|
588 Return true if there are only digit characters, false otherwise. |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents:
13894
diff
changeset
|
589 \end{methoddesc} |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
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13894
diff
changeset
|
590 |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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parents:
13894
diff
changeset
|
591 \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
|
592 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
|
593 there is at least one cased character, false otherwise. |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents:
13894
diff
changeset
|
594 \end{methoddesc} |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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diff
changeset
|
595 |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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parents:
13894
diff
changeset
|
596 \begin{methoddesc}[string]{isspace}{} |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
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13894
diff
changeset
|
597 Return true if there are only whitespace characters in the string and |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents:
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diff
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|
598 the string is not empty, false otherwise. |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
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13894
diff
changeset
|
599 \end{methoddesc} |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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13894
diff
changeset
|
600 |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents:
13894
diff
changeset
|
601 \begin{methoddesc}[string]{istitle}{} |
|
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
|
602 Return true if the string is a titlecased string: uppercase |
|
13933
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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diff
changeset
|
603 characters may only follow uncased characters and lowercase characters |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
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diff
changeset
|
604 only cased ones. Return false otherwise. |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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parents:
13894
diff
changeset
|
605 \end{methoddesc} |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
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13894
diff
changeset
|
606 |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents:
13894
diff
changeset
|
607 \begin{methoddesc}[string]{isupper}{} |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
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13894
diff
changeset
|
608 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>
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13894
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changeset
|
609 there is at least one cased character, false otherwise. |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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changeset
|
610 \end{methoddesc} |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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diff
changeset
|
611 |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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diff
changeset
|
612 \begin{methoddesc}[string]{join}{seq} |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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|
613 Return a string which is the concatenation of the strings in the |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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changeset
|
614 sequence \var{seq}. The separator between elements is the string |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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changeset
|
615 providing this method. |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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diff
changeset
|
616 \end{methoddesc} |
|
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Added Marc-Andre Lemburg's documentation for string methods, with some
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13894
diff
changeset
|
617 |
|
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Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents:
13894
diff
changeset
|
618 \begin{methoddesc}[string]{ljust}{width} |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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diff
changeset
|
619 Return the string left justified in a string of length \var{width}. |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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parents:
13894
diff
changeset
|
620 Padding is done using spaces. The original string is returned if |
|
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Added Marc-Andre Lemburg's documentation for string methods, with some
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diff
changeset
|
621 \var{width} is less than \code{len(\var{s})}. |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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changeset
|
622 \end{methoddesc} |
|
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Added Marc-Andre Lemburg's documentation for string methods, with some
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|
623 |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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changeset
|
624 \begin{methoddesc}[string]{lower}{} |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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parents:
13894
diff
changeset
|
625 Return a copy of the string converted to lowercase. |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
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changeset
|
626 \end{methoddesc} |
|
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Added Marc-Andre Lemburg's documentation for string methods, with some
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|
627 |
|
23017
44637bd7f59b
Document the optional argument to the .strip(), .rstrip(), .strip() string
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changeset
|
628 \begin{methoddesc}[string]{lstrip}{\optional{chars}} |
|
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Document the optional argument to the .strip(), .rstrip(), .strip() string
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|
629 Return a copy of the string with leading characters removed. If |
|
44637bd7f59b
Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
parents:
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changeset
|
630 \var{chars} is omitted or \code{None}, whitespace characters are |
|
44637bd7f59b
Document the optional argument to the .strip(), .rstrip(), .strip() string
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diff
changeset
|
631 removed. If given and not \code{None}, \var{chars} must be a string; |
|
44637bd7f59b
Document the optional argument to the .strip(), .rstrip(), .strip() string
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parents:
22994
diff
changeset
|
632 the characters in the string will be stripped from the beginning of |
|
44637bd7f59b
Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
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diff
changeset
|
633 the string this method is called on. |
|
26259
60d809a25bae
Document that a minor feature was added in 2.2.2. ;-(
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changeset
|
634 \versionchanged[Support for the \var{chars} argument]{2.2.2} |
|
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Added Marc-Andre Lemburg's documentation for string methods, with some
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|
635 \end{methoddesc} |
|
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Added Marc-Andre Lemburg's documentation for string methods, with some
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diff
changeset
|
636 |
|
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Added Marc-Andre Lemburg's documentation for string methods, with some
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diff
changeset
|
637 \begin{methoddesc}[string]{replace}{old, new\optional{, maxsplit}} |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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diff
changeset
|
638 Return a copy of the string with all occurrences of substring |
|
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Added Marc-Andre Lemburg's documentation for string methods, with some
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|
639 \var{old} replaced by \var{new}. If the optional argument |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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changeset
|
640 \var{maxsplit} is given, only the first \var{maxsplit} occurrences are |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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13894
diff
changeset
|
641 replaced. |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents:
13894
diff
changeset
|
642 \end{methoddesc} |
|
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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]{rfind}{sub \optional{,start \optional{,end}}} |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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diff
changeset
|
645 Return the highest index in the string where substring \var{sub} is |
|
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Added Marc-Andre Lemburg's documentation for string methods, with some
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parents:
13894
diff
changeset
|
646 found, such that \var{sub} is contained within s[start,end]. Optional |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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|
647 arguments \var{start} and \var{end} are interpreted as in slice |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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13894
diff
changeset
|
648 notation. Return \code{-1} on failure. |
|
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Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
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changeset
|
649 \end{methoddesc} |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
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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]{rindex}{sub\optional{, start\optional{, end}}} |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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parents:
13894
diff
changeset
|
652 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
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changeset
|
653 substring \var{sub} is not found. |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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changeset
|
654 \end{methoddesc} |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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13894
diff
changeset
|
655 |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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parents:
13894
diff
changeset
|
656 \begin{methoddesc}[string]{rjust}{width} |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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parents:
13894
diff
changeset
|
657 Return the string right justified in a string of length \var{width}. |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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13894
diff
changeset
|
658 Padding is done using spaces. The original string is returned if |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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diff
changeset
|
659 \var{width} is less than \code{len(\var{s})}. |
|
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Added Marc-Andre Lemburg's documentation for string methods, with some
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parents:
13894
diff
changeset
|
660 \end{methoddesc} |
|
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Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents:
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changeset
|
661 |
|
23017
44637bd7f59b
Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
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|
662 \begin{methoddesc}[string]{rstrip}{\optional{chars}} |
|
44637bd7f59b
Document the optional argument to the .strip(), .rstrip(), .strip() string
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22994
diff
changeset
|
663 Return a copy of the string with trailing characters removed. If |
|
44637bd7f59b
Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
parents:
22994
diff
changeset
|
664 \var{chars} is omitted or \code{None}, whitespace characters are |
|
44637bd7f59b
Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
parents:
22994
diff
changeset
|
665 removed. If given and not \code{None}, \var{chars} must be a string; |
|
44637bd7f59b
Document the optional argument to the .strip(), .rstrip(), .strip() string
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parents:
22994
diff
changeset
|
666 the characters in the string will be stripped from the end of the |
|
44637bd7f59b
Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
parents:
22994
diff
changeset
|
667 string this method is called on. |
|
26259
60d809a25bae
Document that a minor feature was added in 2.2.2. ;-(
Fred Drake <fdrake@acm.org>
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26161
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changeset
|
668 \versionchanged[Support for the \var{chars} argument]{2.2.2} |
|
13933
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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parents:
13894
diff
changeset
|
669 \end{methoddesc} |
|
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Added Marc-Andre Lemburg's documentation for string methods, with some
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13894
diff
changeset
|
670 |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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parents:
13894
diff
changeset
|
671 \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>
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|
672 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
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|
673 delimiter string. If \var{maxsplit} is given, at most \var{maxsplit} |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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|
674 splits are done. If \var{sep} is not specified or \code{None}, any |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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diff
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|
675 whitespace string is a separator. |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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diff
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|
676 \end{methoddesc} |
|
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Added Marc-Andre Lemburg's documentation for string methods, with some
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diff
changeset
|
677 |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents:
13894
diff
changeset
|
678 \begin{methoddesc}[string]{splitlines}{\optional{keepends}} |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
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13894
diff
changeset
|
679 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>
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13894
diff
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|
680 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>
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|
681 \var{keepends} is given and true. |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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13894
diff
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|
682 \end{methoddesc} |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
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diff
changeset
|
683 |
|
23017
44637bd7f59b
Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
parents:
22994
diff
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|
684 \begin{methoddesc}[string]{startswith}{prefix\optional{, |
|
44637bd7f59b
Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
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22994
diff
changeset
|
685 start\optional{, end}}} |
|
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Make a start at describing the results of class/type unification
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|
686 Return true if string starts with the \var{prefix}, otherwise |
|
63ee31bb25f3
Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
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23847
diff
changeset
|
687 return 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>
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13894
diff
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|
688 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>
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|
689 position. |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
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diff
changeset
|
690 \end{methoddesc} |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
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|
691 |
|
23017
44637bd7f59b
Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
parents:
22994
diff
changeset
|
692 \begin{methoddesc}[string]{strip}{\optional{chars}} |
|
44637bd7f59b
Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
parents:
22994
diff
changeset
|
693 Return a copy of the string with leading and trailing characters |
|
44637bd7f59b
Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
parents:
22994
diff
changeset
|
694 removed. If \var{chars} is omitted or \code{None}, whitespace |
|
44637bd7f59b
Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
parents:
22994
diff
changeset
|
695 characters are removed. If given and not \code{None}, \var{chars} |
|
44637bd7f59b
Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
parents:
22994
diff
changeset
|
696 must be a string; the characters in the string will be stripped from |
|
44637bd7f59b
Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
parents:
22994
diff
changeset
|
697 the both ends of the string this method is called on. |
|
26259
60d809a25bae
Document that a minor feature was added in 2.2.2. ;-(
Fred Drake <fdrake@acm.org>
parents:
26161
diff
changeset
|
698 \versionchanged[Support for the \var{chars} argument]{2.2.2} |
|
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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 |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents:
13894
diff
changeset
|
701 \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
|
702 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
|
703 lowercase and vice versa. |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents:
13894
diff
changeset
|
704 \end{methoddesc} |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents:
13894
diff
changeset
|
705 |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents:
13894
diff
changeset
|
706 \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
|
707 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
|
708 characters, all remaining cased characters are lowercase. |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents:
13894
diff
changeset
|
709 \end{methoddesc} |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents:
13894
diff
changeset
|
710 |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents:
13894
diff
changeset
|
711 \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
|
712 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
|
713 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
|
714 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
|
715 must be a string of length 256. |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents:
13894
diff
changeset
|
716 \end{methoddesc} |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents:
13894
diff
changeset
|
717 |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents:
13894
diff
changeset
|
718 \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
|
719 Return a copy of the string converted to uppercase. |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents:
13894
diff
changeset
|
720 \end{methoddesc} |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents:
13894
diff
changeset
|
721 |
|
23045
8b1268bc371a
Apply the second version of SF patch http://www.python.org/sf/536241
Walter Dörwald <walter@livinglogic.de>
parents:
23017
diff
changeset
|
722 \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
|
723 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
|
724 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
|
725 \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
|
726 \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
|
727 \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
|
728 |
|
13933
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 \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
|
731 |
|
21177
7d1eac41ce3e
Slightly improved indexing for the string-% operator, thanks to comments
Fred Drake <fdrake@acm.org>
parents:
21163
diff
changeset
|
732 \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
|
733 \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
|
734 \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
|
735 \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
|
736 \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
|
737 \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
|
738 \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
|
739 \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
|
740 |
|
16285
15e0c10092bb
Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents:
15926
diff
changeset
|
741 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
|
742 \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
|
743 \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
|
744 \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
|
745 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
|
746 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
|
747 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
|
748 \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
|
749 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
|
750 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
|
751 |
|
15e0c10092bb
Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents:
15926
diff
changeset
|
752 If \var{format} requires a single argument, \var{values} may be a |
|
23860
63ee31bb25f3
Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents:
23847
diff
changeset
|
753 single non-tuple object. \footnote{To format only a tuple you |
|
63ee31bb25f3
Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents:
23847
diff
changeset
|
754 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
|
755 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
|
756 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
|
757 single mapping object (for example, a dictionary). |
|
15e0c10092bb
Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents:
15926
diff
changeset
|
758 |
|
15e0c10092bb
Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents:
15926
diff
changeset
|
759 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
|
760 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
|
761 |
|
16285
15e0c10092bb
Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents:
15926
diff
changeset
|
762 \begin{enumerate} |
|
15e0c10092bb
Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents:
15926
diff
changeset
|
763 \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
|
764 specifier. |
|
23860
63ee31bb25f3
Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents:
23847
diff
changeset
|
765 \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
|
766 of characters (for example, \code{(somename)}). |
|
16285
15e0c10092bb
Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents:
15926
diff
changeset
|
767 \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
|
768 conversion types. |
|
15e0c10092bb
Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents:
15926
diff
changeset
|
769 \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
|
770 \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
|
771 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
|
772 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
|
773 precision. |
|
15e0c10092bb
Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents:
15926
diff
changeset
|
774 \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
|
775 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
|
776 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
|
777 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
|
778 the precision. |
|
15e0c10092bb
Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents:
15926
diff
changeset
|
779 \item Length modifier (optional). |
|
15e0c10092bb
Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents:
15926
diff
changeset
|
780 \item Conversion type. |
|
15e0c10092bb
Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents:
15926
diff
changeset
|
781 \end{enumerate} |
|
8730
8a306dfd9f33
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|
782 |
|
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|
783 When the right argument is a dictionary (or other mapping type), then |
|
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|
784 the formats in the string \emph{must} include a parenthesised mapping key into |
|
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785 that dictionary inserted immediately after the \character{\%} |
|
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|
786 character. The mapping key selects the value to be formatted from the |
|
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787 mapping. For example: |
|
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|
788 |
|
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|
789 \begin{verbatim} |
|
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|
790 >>> print '%(language)s has %(#)03d quote types.' % \ |
|
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|
791 {'language': "Python", "#": 2} |
|
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792 Python has 002 quote types. |
|
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|
793 \end{verbatim} |
|
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|
794 |
|
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|
795 In this case no \code{*} specifiers may occur in a format (since they |
|
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|
796 require a sequential parameter list). |
|
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|
797 |
|
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|
798 The conversion flag characters are: |
|
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|
799 |
|
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800 \begin{tableii}{c|l}{character}{Flag}{Meaning} |
|
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|
801 \lineii{\#}{The value conversion will use the ``alternate form'' |
|
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802 (where defined below).} |
|
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803 \lineii{0}{The conversion will be zero padded for numeric values.} |
|
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804 \lineii{-}{The converted value is left adjusted (overrides |
|
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805 the \character{0} conversion if both are given).} |
|
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806 \lineii{{~}}{(a space) A blank should be left before a positive number |
|
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|
807 (or empty string) produced by a signed conversion.} |
|
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808 \lineii{+}{A sign character (\character{+} or \character{-}) will |
|
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809 precede the conversion (overrides a "space" flag).} |
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810 \end{tableii} |
|
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|
811 |
|
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812 The length modifier may be \code{h}, \code{l}, and \code{L} may be |
|
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813 present, but are ignored as they are not necessary for Python. |
|
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|
814 |
|
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|
815 The conversion types are: |
|
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|
816 |
|
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|
817 \begin{tableiii}{c|l|c}{character}{Conversion}{Meaning}{Notes} |
|
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|
818 \lineiii{d}{Signed integer decimal.}{} |
|
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|
819 \lineiii{i}{Signed integer decimal.}{} |
|
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- The "-" format flag overrides the "0" flag, not the "-" flag.
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820 \lineiii{o}{Unsigned octal.}{(1)} |
|
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- The "-" format flag overrides the "0" flag, not the "-" flag.
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|
821 \lineiii{u}{Unsigned decimal.}{} |
|
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|
822 \lineiii{x}{Unsigned hexidecimal (lowercase).}{(2)} |
|
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|
823 \lineiii{X}{Unsigned hexidecimal (uppercase).}{(2)} |
|
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|
824 \lineiii{e}{Floating point exponential format (lowercase).}{} |
|
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|
825 \lineiii{E}{Floating point exponential format (uppercase).}{} |
|
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826 \lineiii{f}{Floating point decimal format.}{} |
|
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|
827 \lineiii{F}{Floating point decimal format.}{} |
|
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|
828 \lineiii{g}{Same as \character{e} if exponent is greater than -4 or |
|
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|
829 less than precision, \character{f} otherwise.}{} |
|
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830 \lineiii{G}{Same as \character{E} if exponent is greater than -4 or |
|
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|
831 less than precision, \character{F} otherwise.}{} |
|
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832 \lineiii{c}{Single character (accepts integer or single character |
|
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|
833 string).}{} |
|
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|
834 \lineiii{r}{String (converts any python object using |
|
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|
835 \function{repr()}).}{(3)} |
|
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|
836 \lineiii{s}{String (converts any python object using |
|
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837 \function{str()}).}{(4)} |
|
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|
838 \lineiii{\%}{No argument is converted, results in a \character{\%} |
|
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|
839 character in the result.}{} |
|
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|
840 \end{tableiii} |
|
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- The "-" format flag overrides the "0" flag, not the "-" flag.
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|
841 |
|
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- The "-" format flag overrides the "0" flag, not the "-" flag.
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|
842 \noindent |
|
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|
843 Notes: |
|
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|
844 \begin{description} |
|
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- The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
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|
845 \item[(1)] |
|
50905db35da5
- The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
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|
846 The alternate form causes a leading zero (\character{0}) to be |
|
50905db35da5
- The "-" format flag overrides the "0" flag, not the "-" flag.
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|
847 inserted between left-hand padding and the formatting of the |
|
50905db35da5
- The "-" format flag overrides the "0" flag, not the "-" flag.
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848 number if the leading character of the result is not already a |
|
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- The "-" format flag overrides the "0" flag, not the "-" flag.
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|
849 zero. |
|
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- The "-" format flag overrides the "0" flag, not the "-" flag.
Fred Drake <fdrake@acm.org>
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|
850 \item[(2)] |
|
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Fred Drake <fdrake@acm.org>
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|
851 The alternate form causes a leading \code{'0x'} or \code{'0X'} |
|
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- The "-" format flag overrides the "0" flag, not the "-" flag.
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|
852 (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>
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|
853 was used) to be inserted between left-hand padding and the |
|
50905db35da5
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Fred Drake <fdrake@acm.org>
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|
854 formatting of the number if the leading character of the result is |
|
50905db35da5
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|
855 not already a zero. |
|
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Fred Drake <fdrake@acm.org>
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|
856 \item[(3)] |
|
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|
857 The \code{\%r} conversion was added in Python 2.0. |
|
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|
858 \item[(4)] |
|
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Raymond Hettinger <python@rcn.com>
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|
859 If the object or format provided is a \class{unicode} string, |
|
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|
860 the resulting string will also be \class{unicode}. |
|
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|
861 \end{description} |
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862 |
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|
863 % XXX Examples? |
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|
864 |
|
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|
865 Since Python strings have an explicit length, \code{\%s} conversions |
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866 do not assume that \code{'\e0'} is the end of the string. |
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|
867 |
|
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|
868 For safety reasons, floating point precisions are clipped to 50; |
|
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|
869 \code{\%f} conversions for numbers whose absolute value is over 1e25 |
|
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|
870 are replaced by \code{\%g} conversions.\footnote{ |
|
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|
871 These numbers are fairly arbitrary. They are intended to |
|
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|
872 avoid printing endless strings of meaningless digits without hampering |
|
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|
873 correct use and without having to know the exact precision of floating |
|
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|
874 point values on a particular machine. |
|
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|
875 } All other errors raise exceptions. |
|
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|
876 |
|
21163
7b6879714b74
Make no assumption about how modules are built when referring to them; this
Fred Drake <fdrake@acm.org>
parents:
21159
diff
changeset
|
877 Additional string operations are defined in standard modules |
|
7b6879714b74
Make no assumption about how modules are built when referring to them; this
Fred Drake <fdrake@acm.org>
parents:
21159
diff
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|
878 \refmodule{string}\refstmodindex{string} and |
|
22241
7584b6f1afde
Change Windows file.truncate() to (a) restore the original file position,
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diff
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|
879 \refmodule{re}.\refstmodindex{re} |
|
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|
880 |
|
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Fred Drake <fdrake@acm.org>
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|
881 |
|
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As pointed out by Denis S. Otkidach <den@analyt.chem.msu.ru>, xrange()
Fred Drake <fdrake@acm.org>
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|
882 \subsubsection{XRange Type \label{typesseq-xrange}} |
|
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|
883 |
|
15005
0cf5111bf09c
Use \obindex{...} instead of \indexii{...}{type} in many places; this is
Fred Drake <fdrake@acm.org>
parents:
14710
diff
changeset
|
884 The xrange\obindex{xrange} type is an immutable sequence which is |
|
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Fred Drake <fdrake@acm.org>
parents:
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diff
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|
885 commonly used for looping. The advantage of the xrange type is that an |
|
a905c5aa0691
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Fred Drake <fdrake@acm.org>
parents:
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|
886 xrange object will always take the same amount of memory, no matter the |
|
13967
7b7ee58901fb
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13933
diff
changeset
|
887 size of the range it represents. There are no consistent performance |
|
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parents:
13933
diff
changeset
|
888 advantages. |
|
7b7ee58901fb
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changeset
|
889 |
|
26592
0c646baeec58
Update comments about the performance of xrange().
Raymond Hettinger <python@rcn.com>
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|
890 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
|
891 iteration, and the \function{len()} function. |
|
13967
7b7ee58901fb
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Fred Drake <fdrake@acm.org>
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diff
changeset
|
892 |
|
7b7ee58901fb
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Fred Drake <fdrake@acm.org>
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13933
diff
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|
893 |
|
10156
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Make sure all HTML pages generated from this section have reasonable
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|
894 \subsubsection{Mutable Sequence Types \label{typesseq-mutable}} |
|
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|
895 |
|
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|
896 List objects support additional operations that allow in-place |
|
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|
897 modification of the object. |
|
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diff
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|
898 Other mutable sequence types (when added to the language) should |
|
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Make a start at describing the results of class/type unification
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diff
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|
899 also support these operations. |
|
63ee31bb25f3
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diff
changeset
|
900 Strings and tuples are immutable sequence types: such objects cannot |
|
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diff
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|
901 be modified once created. |
|
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diff
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|
902 The following operations are defined on mutable sequence types (where |
|
8a306dfd9f33
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|
903 \var{x} is an arbitrary object): |
|
8a306dfd9f33
Move files around to get the names to match the module names except for
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diff
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|
904 \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
|
905 \obindex{list} |
|
8730
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diff
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|
906 |
|
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diff
changeset
|
907 \begin{tableiii}{c|l|c}{code}{Operation}{Result}{Notes} |
|
8a306dfd9f33
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|
908 \lineiii{\var{s}[\var{i}] = \var{x}} |
|
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|
909 {item \var{i} of \var{s} is replaced by \var{x}}{} |
|
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|
910 \lineiii{\var{s}[\var{i}:\var{j}] = \var{t}} |
|
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|
911 {slice of \var{s} from \var{i} to \var{j} is replaced by \var{t}}{} |
|
8a306dfd9f33
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|
912 \lineiii{del \var{s}[\var{i}:\var{j}]} |
|
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|
913 {same as \code{\var{s}[\var{i}:\var{j}] = []}}{} |
|
8a306dfd9f33
Move files around to get the names to match the module names except for
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diff
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|
914 \lineiii{\var{s}.append(\var{x})} |
|
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|
915 {same as \code{\var{s}[len(\var{s}):len(\var{s})] = [\var{x}]}}{(1)} |
|
9318
8a26e55e18b8
Document the new list.extend() method. Interesting enough, the
Barry Warsaw <barry@python.org>
parents:
9083
diff
changeset
|
916 \lineiii{\var{s}.extend(\var{x})} |
|
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|
917 {same as \code{\var{s}[len(\var{s}):len(\var{s})] = \var{x}}}{(2)} |
|
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|
918 \lineiii{\var{s}.count(\var{x})} |
|
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|
919 {return number of \var{i}'s for which \code{\var{s}[\var{i}] == \var{x}}}{} |
|
8a306dfd9f33
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|
920 \lineiii{\var{s}.index(\var{x})} |
|
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diff
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|
921 {return smallest \var{i} such that \code{\var{s}[\var{i}] == \var{x}}}{(3)} |
|
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diff
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|
922 \lineiii{\var{s}.insert(\var{i}, \var{x})} |
|
8a306dfd9f33
Move files around to get the names to match the module names except for
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diff
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|
923 {same as \code{\var{s}[\var{i}:\var{i}] = [\var{x}]} |
|
23860
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Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents:
23847
diff
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|
924 if \code{\var{i} >= 0}}{(4)} |
|
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diff
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|
925 \lineiii{\var{s}.pop(\optional{\var{i}})} |
|
23860
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Make a start at describing the results of class/type unification
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parents:
23847
diff
changeset
|
926 {same as \code{\var{x} = \var{s}[\var{i}]; del \var{s}[\var{i}]; return \var{x}}}{(5)} |
|
8730
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parents:
diff
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|
927 \lineiii{\var{s}.remove(\var{x})} |
|
23860
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parents:
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diff
changeset
|
928 {same as \code{del \var{s}[\var{s}.index(\var{x})]}}{(3)} |
|
8730
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diff
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|
929 \lineiii{\var{s}.reverse()} |
|
23860
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parents:
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diff
changeset
|
930 {reverses the items of \var{s} in place}{(6)} |
|
27036
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Allow list sort's comparison function to explicitly be None. See SF patch
Skip Montanaro <skip@pobox.com>
parents:
26816
diff
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|
931 \lineiii{\var{s}.sort(\optional{\var{cmpfunc=None}})} |
|
26161
dd10d97d329a
SF patch 637176: list.sort crasher
Tim Peters <tim.peters@gmail.com>
parents:
25906
diff
changeset
|
932 {sort the items of \var{s} in place}{(6), (7), (8), (9)} |
|
8730
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Fred Drake <fdrake@acm.org>
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diff
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|
933 \end{tableiii} |
|
8a306dfd9f33
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diff
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|
934 \indexiv{operations on}{mutable}{sequence}{types} |
|
8a306dfd9f33
Move files around to get the names to match the module names except for
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diff
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|
935 \indexiii{operations on}{sequence}{types} |
|
8a306dfd9f33
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parents:
diff
changeset
|
936 \indexiii{operations on}{list}{type} |
|
8a306dfd9f33
Move files around to get the names to match the module names except for
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diff
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|
937 \indexii{subscript}{assignment} |
|
8a306dfd9f33
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diff
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|
938 \indexii{slice}{assignment} |
|
8a306dfd9f33
Move files around to get the names to match the module names except for
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parents:
diff
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|
939 \stindex{del} |
|
10156
0f7d694bc334
Make sure all HTML pages generated from this section have reasonable
Fred Drake <fdrake@acm.org>
parents:
10147
diff
changeset
|
940 \withsubitem{(list method)}{ |
|
11183
1e0b1967be7f
In note mentioning [].remove()'s exception, tell what exception is
Fred Drake <fdrake@acm.org>
parents:
11100
diff
changeset
|
941 \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
|
942 \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
|
943 \ttindex{sort()}} |
|
8730
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Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff
changeset
|
944 \noindent |
|
8a306dfd9f33
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Fred Drake <fdrake@acm.org>
parents:
diff
changeset
|
945 Notes: |
|
8a306dfd9f33
Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff
changeset
|
946 \begin{description} |
|
23860
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Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents:
23847
diff
changeset
|
947 \item[(1)] The C implementation of Python historically accepted |
|
63ee31bb25f3
Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents:
23847
diff
changeset
|
948 multiple parameters and implicitly joined them into a tuple; |
|
63ee31bb25f3
Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents:
23847
diff
changeset
|
949 Use of this misfeature has been deprecated since Python 1.4, |
|
63ee31bb25f3
Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents:
23847
diff
changeset
|
950 and became an error with the introduction of Python 2.0. |
|
23778
245224d1b8c9
This is my nearly two year old patch
Michael W. Hudson <mwh@python.net>
parents:
23515
diff
changeset
|
951 |
|
26816
6932794817c2
SF Bug 645777: list.extend() works with any iterable and is no longer
Raymond Hettinger <python@rcn.com>
parents:
26672
diff
changeset
|
952 \item[(2)] Raises an exception when \var{x} is not an iterable object. |
|
12223
e82e82b3b9ad
Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents:
11463
diff
changeset
|
953 |
|
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Make a start at describing the results of class/type unification
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diff
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|
954 \item[(3)] Raises \exception{ValueError} when \var{x} is not found in |
|
11183
1e0b1967be7f
In note mentioning [].remove()'s exception, tell what exception is
Fred Drake <fdrake@acm.org>
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11100
diff
changeset
|
955 \var{s}. |
|
1e0b1967be7f
In note mentioning [].remove()'s exception, tell what exception is
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parents:
11100
diff
changeset
|
956 |
|
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Steve Holden <steve@holdenweb.com>
parents:
23847
diff
changeset
|
957 \item[(4)] When a negative index is passed as the first parameter to |
|
20701
5f6850d1f9e8
Explain what [].insert() does when the target index is negative.
Fred Drake <fdrake@acm.org>
parents:
20580
diff
changeset
|
958 the \method{insert()} method, the new element is prepended to the |
|
5f6850d1f9e8
Explain what [].insert() does when the target index is negative.
Fred Drake <fdrake@acm.org>
parents:
20580
diff
changeset
|
959 sequence. |
|
5f6850d1f9e8
Explain what [].insert() does when the target index is negative.
Fred Drake <fdrake@acm.org>
parents:
20580
diff
changeset
|
960 |
|
23860
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Make a start at describing the results of class/type unification
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diff
changeset
|
961 \item[(5)] 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
|
962 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
|
963 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>
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11463
diff
changeset
|
964 |
|
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|
965 \item[(6)] 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
|
966 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
|
967 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
|
968 the sorted or reversed list. |
|
12223
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Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
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11463
diff
changeset
|
969 |
|
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diff
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|
970 \item[(7)] The \method{sort()} method takes an optional argument |
|
8730
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diff
changeset
|
971 specifying a comparison function of two arguments (list items) which |
|
20173
f100793ca9af
The list.sort() docs require a function that returns -1, 0 or +1. That's
Tim Peters <tim.peters@gmail.com>
parents:
20045
diff
changeset
|
972 should return a negative, zero or positive number depending on whether |
|
11183
1e0b1967be7f
In note mentioning [].remove()'s exception, tell what exception is
Fred Drake <fdrake@acm.org>
parents:
11100
diff
changeset
|
973 the first argument is considered smaller than, equal to, or larger |
|
1e0b1967be7f
In note mentioning [].remove()'s exception, tell what exception is
Fred Drake <fdrake@acm.org>
parents:
11100
diff
changeset
|
974 than the second argument. Note that this slows the sorting process |
|
1e0b1967be7f
In note mentioning [].remove()'s exception, tell what exception is
Fred Drake <fdrake@acm.org>
parents:
11100
diff
changeset
|
975 down considerably; e.g. to sort a list in reverse order it is much |
|
27036
41f7726e3e51
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Skip Montanaro <skip@pobox.com>
parents:
26816
diff
changeset
|
976 faster to call method \method{sort()} followed by \method{reverse()} |
|
41f7726e3e51
Allow list sort's comparison function to explicitly be None. See SF patch
Skip Montanaro <skip@pobox.com>
parents:
26816
diff
changeset
|
977 than to use method \method{sort()} with a comparison function that |
|
41f7726e3e51
Allow list sort's comparison function to explicitly be None. See SF patch
Skip Montanaro <skip@pobox.com>
parents:
26816
diff
changeset
|
978 reverses the ordering of the elements. Passing \constant{None} as the |
|
41f7726e3e51
Allow list sort's comparison function to explicitly be None. See SF patch
Skip Montanaro <skip@pobox.com>
parents:
26816
diff
changeset
|
979 comparison function is semantically equivalent to calling |
|
41f7726e3e51
Allow list sort's comparison function to explicitly be None. See SF patch
Skip Montanaro <skip@pobox.com>
parents:
26816
diff
changeset
|
980 \method{sort()} with no comparison function. |
|
24459
189eb6fa9ded
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Tim Peters <tim.peters@gmail.com>
parents:
24253
diff
changeset
|
981 |
|
189eb6fa9ded
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Tim Peters <tim.peters@gmail.com>
parents:
24253
diff
changeset
|
982 \item[(8)] Whether the \method{sort()} method is stable is not defined by |
|
189eb6fa9ded
Added new footnote about list.sort() stability. Repaired footnote about
Tim Peters <tim.peters@gmail.com>
parents:
24253
diff
changeset
|
983 the language (a sort is stable if it guarantees not to change the |
|
189eb6fa9ded
Added new footnote about list.sort() stability. Repaired footnote about
Tim Peters <tim.peters@gmail.com>
parents:
24253
diff
changeset
|
984 relative order of elements that compare equal). In the C |
|
189eb6fa9ded
Added new footnote about list.sort() stability. Repaired footnote about
Tim Peters <tim.peters@gmail.com>
parents:
24253
diff
changeset
|
985 implementation of Python, sorts were stable only by accident through |
|
189eb6fa9ded
Added new footnote about list.sort() stability. Repaired footnote about
Tim Peters <tim.peters@gmail.com>
parents:
24253
diff
changeset
|
986 Python 2.2. The C implementation of Python 2.3 introduced a stable |
|
189eb6fa9ded
Added new footnote about list.sort() stability. Repaired footnote about
Tim Peters <tim.peters@gmail.com>
parents:
24253
diff
changeset
|
987 \method{sort()} method, but code that intends to be portable across |
|
189eb6fa9ded
Added new footnote about list.sort() stability. Repaired footnote about
Tim Peters <tim.peters@gmail.com>
parents:
24253
diff
changeset
|
988 implementations and versions must not rely on stability. |
|
26161
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SF patch 637176: list.sort crasher
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parents:
25906
diff
changeset
|
989 |
|
dd10d97d329a
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Tim Peters <tim.peters@gmail.com>
parents:
25906
diff
changeset
|
990 \item[(9)] While a list is being sorted, the effect of attempting to |
|
dd10d97d329a
SF patch 637176: list.sort crasher
Tim Peters <tim.peters@gmail.com>
parents:
25906
diff
changeset
|
991 mutate, or even inspect, the list is undefined. The C implementation |
|
dd10d97d329a
SF patch 637176: list.sort crasher
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parents:
25906
diff
changeset
|
992 of Python 2.3 makes the list appear empty for the duration, and raises |
|
dd10d97d329a
SF patch 637176: list.sort crasher
Tim Peters <tim.peters@gmail.com>
parents:
25906
diff
changeset
|
993 \exception{ValueError} if it can detect that the list has been |
|
dd10d97d329a
SF patch 637176: list.sort crasher
Tim Peters <tim.peters@gmail.com>
parents:
25906
diff
changeset
|
994 mutated during a sort. |
|
8730
8a306dfd9f33
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parents:
diff
changeset
|
995 \end{description} |
|
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996 |
|
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|
997 |
| 9083 | 998 \subsection{Mapping Types \label{typesmapping}} |
|
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999 \obindex{mapping} |
|
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|
1000 \obindex{dictionary} |
|
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1001 |
|
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1002 A \dfn{mapping} object maps immutable values to |
|
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1003 arbitrary objects. Mappings are mutable objects. There is currently |
|
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|
1004 only one standard mapping type, the \dfn{dictionary}. A dictionary's keys are |
|
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|
1005 almost arbitrary values. Only values containing lists, dictionaries |
|
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|
1006 or other mutable types (that are compared by value rather than by |
|
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Make a start at describing the results of class/type unification
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|
1007 object identity) may not be used as keys. |
|
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|
1008 Numeric types used for keys obey the normal rules for numeric |
|
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|
1009 comparison: if two numbers compare equal (e.g. \code{1} and |
|
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|
1010 \code{1.0}) then they can be used interchangeably to index the same |
|
8a306dfd9f33
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diff
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|
1011 dictionary entry. |
|
8a306dfd9f33
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diff
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|
1012 |
|
8a306dfd9f33
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|
1013 Dictionaries are created by placing a comma-separated list of |
|
8a306dfd9f33
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parents:
diff
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|
1014 \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
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|
1015 \code{\{'jack': 4098, 'sjoerd': 4127\}} or |
|
8a306dfd9f33
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|
1016 \code{\{4098: 'jack', 4127: 'sjoerd'\}}. |
|
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|
1017 |
|
10968
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|
1018 The following operations are defined on mappings (where \var{a} and |
|
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Some clarifications on operations for mapping types, based on comments
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|
1019 \var{b} are mappings, \var{k} is a key, and \var{v} and \var{x} are |
|
5ba2e4ce58cb
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|
1020 arbitrary objects): |
|
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|
1021 \indexiii{operations on}{mapping}{types} |
|
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|
1022 \indexiii{operations on}{dictionary}{type} |
|
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Move files around to get the names to match the module names except for
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diff
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|
1023 \stindex{del} |
|
8a306dfd9f33
Move files around to get the names to match the module names except for
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diff
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|
1024 \bifuncindex{len} |
|
10156
0f7d694bc334
Make sure all HTML pages generated from this section have reasonable
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diff
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|
1025 \withsubitem{(dictionary method)}{ |
|
0f7d694bc334
Make sure all HTML pages generated from this section have reasonable
Fred Drake <fdrake@acm.org>
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diff
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|
1026 \ttindex{clear()} |
|
0f7d694bc334
Make sure all HTML pages generated from this section have reasonable
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diff
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|
1027 \ttindex{copy()} |
|
0f7d694bc334
Make sure all HTML pages generated from this section have reasonable
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diff
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|
1028 \ttindex{has_key()} |
|
0f7d694bc334
Make sure all HTML pages generated from this section have reasonable
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diff
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|
1029 \ttindex{items()} |
|
0f7d694bc334
Make sure all HTML pages generated from this section have reasonable
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diff
changeset
|
1030 \ttindex{keys()} |
|
0f7d694bc334
Make sure all HTML pages generated from this section have reasonable
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diff
changeset
|
1031 \ttindex{update()} |
|
0f7d694bc334
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diff
changeset
|
1032 \ttindex{values()} |
|
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|
1033 \ttindex{get()}} |
|
10968
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diff
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|
1034 |
|
5ba2e4ce58cb
Some clarifications on operations for mapping types, based on comments
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diff
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|
1035 \begin{tableiii}{c|l|c}{code}{Operation}{Result}{Notes} |
|
5ba2e4ce58cb
Some clarifications on operations for mapping types, based on comments
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10785
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changeset
|
1036 \lineiii{len(\var{a})}{the number of items in \var{a}}{} |
|
5ba2e4ce58cb
Some clarifications on operations for mapping types, based on comments
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parents:
10785
diff
changeset
|
1037 \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
|
1038 \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
|
1039 {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>
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10785
diff
changeset
|
1040 {} |
|
5ba2e4ce58cb
Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents:
10785
diff
changeset
|
1041 \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
|
1042 {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
|
1043 {(1)} |
|
5ba2e4ce58cb
Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
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10785
diff
changeset
|
1044 \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
|
1045 \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
|
1046 \lineiii{\var{a}.has_key(\var{k})} |
|
17594
bf94af396b1e
Implement, test and document "key in dict" and "key not in dict".
Guido van Rossum <guido@python.org>
parents:
16778
diff
changeset
|
1047 {\code{1} if \var{a} has a key \var{k}, else \code{0}} |
|
bf94af396b1e
Implement, test and document "key in dict" and "key not in dict".
Guido van Rossum <guido@python.org>
parents:
16778
diff
changeset
|
1048 {} |
|
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
|
1049 \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
|
1050 {Equivalent to \var{a}.has_key(\var{k})} |
|
17966
178bedf9536d
Add descriptions of {}.iteritems(), {}.iterkeys(), and {}.itervalues()
Fred Drake <fdrake@acm.org>
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17663
diff
changeset
|
1051 {(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
|
1052 \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
|
1053 {Equivalent to \code{not} \var{a}.has_key(\var{k})} |
|
17966
178bedf9536d
Add descriptions of {}.iteritems(), {}.iterkeys(), and {}.itervalues()
Fred Drake <fdrake@acm.org>
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|
1054 {(2)} |
|
10968
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Some clarifications on operations for mapping types, based on comments
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diff
changeset
|
1055 \lineiii{\var{a}.items()} |
|
5ba2e4ce58cb
Some clarifications on operations for mapping types, based on comments
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10785
diff
changeset
|
1056 {a copy of \var{a}'s list of (\var{key}, \var{value}) pairs} |
|
17966
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Add descriptions of {}.iteritems(), {}.iterkeys(), and {}.itervalues()
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changeset
|
1057 {(3)} |
|
18085
7e459fb3c332
Fixed reference to table notes for {}.keys() and {}.items() -- these
Fred Drake <fdrake@acm.org>
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17966
diff
changeset
|
1058 \lineiii{\var{a}.keys()}{a copy of \var{a}'s list of keys}{(3)} |
|
10968
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Some clarifications on operations for mapping types, based on comments
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10785
diff
changeset
|
1059 \lineiii{\var{a}.update(\var{b})} |
|
26437
57d03375aead
SF Patch 643443. Added dict.fromkeys(iterable, value=None), a class
Raymond Hettinger <python@rcn.com>
parents:
26260
diff
changeset
|
1060 {\code{for \var{k} in \var{b}.keys(): \var{a}[\var{k}] = \var{b}[\var{k}]}} |
|
18286
bc05a95242a3
Remove the restriction on a mapping's .update() method.
Barry Warsaw <barry@python.org>
parents:
18085
diff
changeset
|
1061 {} |
|
26437
57d03375aead
SF Patch 643443. Added dict.fromkeys(iterable, value=None), a class
Raymond Hettinger <python@rcn.com>
parents:
26260
diff
changeset
|
1062 \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
|
1063 {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
|
1064 {(7)} |
|
18085
7e459fb3c332
Fixed reference to table notes for {}.keys() and {}.items() -- these
Fred Drake <fdrake@acm.org>
parents:
17966
diff
changeset
|
1065 \lineiii{\var{a}.values()}{a copy of \var{a}'s list of values}{(3)} |
|
10968
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Some clarifications on operations for mapping types, based on comments
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parents:
10785
diff
changeset
|
1066 \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
|
1067 {\code{\var{a}[\var{k}]} if \code{\var{k} in \var{a}}, |
|
10968
5ba2e4ce58cb
Some clarifications on operations for mapping types, based on comments
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10785
diff
changeset
|
1068 else \var{x}} |
|
18286
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Remove the restriction on a mapping's .update() method.
Barry Warsaw <barry@python.org>
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diff
changeset
|
1069 {(4)} |
|
13894
77b9e041b595
Barry's patch to document the new setdefault() method. Slightly
Guido van Rossum <guido@python.org>
parents:
13780
diff
changeset
|
1070 \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
|
1071 {\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
|
1072 else \var{x} (also setting it)} |
|
18286
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Remove the restriction on a mapping's .update() method.
Barry Warsaw <barry@python.org>
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|
1073 {(5)} |
|
22994
196dfa7ed348
Add Raymond Hettinger's d.pop(). See SF patch 539949.
Guido van Rossum <guido@python.org>
parents:
22920
diff
changeset
|
1074 \lineiii{\var{a}.pop(\var{k})} |
|
196dfa7ed348
Add Raymond Hettinger's d.pop(). See SF patch 539949.
Guido van Rossum <guido@python.org>
parents:
22920
diff
changeset
|
1075 {remove specified \var{key} and return corresponding \var{value}} |
|
196dfa7ed348
Add Raymond Hettinger's d.pop(). See SF patch 539949.
Guido van Rossum <guido@python.org>
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22920
diff
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|
1076 {} |
|
15522
aaa54752e4ba
"Documentation" for {}.popitem().
Guido van Rossum <guido@python.org>
parents:
15463
diff
changeset
|
1077 \lineiii{\var{a}.popitem()} |
|
aaa54752e4ba
"Documentation" for {}.popitem().
Guido van Rossum <guido@python.org>
parents:
15463
diff
changeset
|
1078 {remove and return an arbitrary (\var{key}, \var{value}) pair} |
|
18286
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Remove the restriction on a mapping's .update() method.
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|
1079 {(6)} |
|
17966
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|
1080 \lineiii{\var{a}.iteritems()} |
|
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|
1081 {return an iterator over (\var{key}, \var{value}) pairs} |
|
24902
f57d6db423f2
Extend some comments on the order of values in the returns from
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|
1082 {(2), (3)} |
|
17966
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|
1083 \lineiii{\var{a}.iterkeys()} |
|
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changeset
|
1084 {return an iterator over the mapping's keys} |
|
24902
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Extend some comments on the order of values in the returns from
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|
1085 {(2), (3)} |
|
17966
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|
1086 \lineiii{\var{a}.itervalues()} |
|
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|
1087 {return an iterator over the mapping's values} |
|
24902
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|
1088 {(2), (3)} |
|
10968
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|
1089 \end{tableiii} |
|
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changeset
|
1090 |
|
8730
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changeset
|
1091 \noindent |
|
8a306dfd9f33
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diff
changeset
|
1092 Notes: |
|
8a306dfd9f33
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diff
changeset
|
1093 \begin{description} |
|
10968
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Some clarifications on operations for mapping types, based on comments
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diff
changeset
|
1094 \item[(1)] Raises a \exception{KeyError} exception if \var{k} is not |
|
5ba2e4ce58cb
Some clarifications on operations for mapping types, based on comments
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changeset
|
1095 in the map. |
|
8730
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|
1096 |
|
17966
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changeset
|
1097 \item[(2)] \versionadded{2.2} |
|
178bedf9536d
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changeset
|
1098 |
|
178bedf9536d
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diff
changeset
|
1099 \item[(3)] Keys and values are listed in random order. If |
|
24902
f57d6db423f2
Extend some comments on the order of values in the returns from
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parents:
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diff
changeset
|
1100 \method{items()}, \method{keys()}, \method{values()}, |
|
f57d6db423f2
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diff
changeset
|
1101 \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
|
1102 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
|
1103 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
|
1104 \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
|
1105 \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
|
1106 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
|
1107 \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
|
1108 \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
|
1109 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
|
1110 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
|
1111 |
|
18286
bc05a95242a3
Remove the restriction on a mapping's .update() method.
Barry Warsaw <barry@python.org>
parents:
18085
diff
changeset
|
1112 \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
|
1113 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
|
1114 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
|
1115 |
|
18286
bc05a95242a3
Remove the restriction on a mapping's .update() method.
Barry Warsaw <barry@python.org>
parents:
18085
diff
changeset
|
1116 \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
|
1117 that if \var{k} is missing, \var{x} is both returned and inserted into |
|
77b9e041b595
Barry's patch to document the new setdefault() method. Slightly
Guido van Rossum <guido@python.org>
parents:
13780
diff
changeset
|
1118 the dictionary as the value of \var{k}. |
|
15522
aaa54752e4ba
"Documentation" for {}.popitem().
Guido van Rossum <guido@python.org>
parents:
15463
diff
changeset
|
1119 |
|
18286
bc05a95242a3
Remove the restriction on a mapping's .update() method.
Barry Warsaw <barry@python.org>
parents:
18085
diff
changeset
|
1120 \item[(6)] \function{popitem()} is useful to destructively iterate |
|
15522
aaa54752e4ba
"Documentation" for {}.popitem().
Guido van Rossum <guido@python.org>
parents:
15463
diff
changeset
|
1121 over a dictionary, as often used in set algorithms. |
|
8730
8a306dfd9f33
Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff
changeset
|
1122 |
|
26437
57d03375aead
SF Patch 643443. Added dict.fromkeys(iterable, value=None), a class
Raymond Hettinger <python@rcn.com>
parents:
26260
diff
changeset
|
1123 \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
|
1124 new dictionary. \var{value} defaults to \code{None}. \versionadded{2.3} |
|
57d03375aead
SF Patch 643443. Added dict.fromkeys(iterable, value=None), a class
Raymond Hettinger <python@rcn.com>
parents:
26260
diff
changeset
|
1125 \end{description} |
|
57d03375aead
SF Patch 643443. Added dict.fromkeys(iterable, value=None), a class
Raymond Hettinger <python@rcn.com>
parents:
26260
diff
changeset
|
1126 |
|
8730
8a306dfd9f33
Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff
changeset
|
1127 |
|
20767
b3f48c5d6e16
Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents:
20764
diff
changeset
|
1128 \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
|
1129 \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
|
1130 |
|
20767
b3f48c5d6e16
Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents:
20764
diff
changeset
|
1131 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
|
1132 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
|
1133 \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
|
1134 \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
|
1135 is new in Python 2.2. The older built-in \function{open()} is an |
|
37b8d92e12f5
Mention the new file() builtin in the section on file objects.
Tim Peters <tim.peters@gmail.com>
parents:
20701
diff
changeset
|
1136 alias for \function{file()}.} |
|
23860
63ee31bb25f3
Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents:
23847
diff
changeset
|
1137 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
|
1138 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
|
1139 \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
|
1140 \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
|
1141 \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
|
1142 \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
|
1143 |
|
8a306dfd9f33
Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff
changeset
|
1144 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
|
1145 \exception{IOError} is raised. This includes situations where the |
|
fa867d8ee7eb
Remove some remaining {\rm ...} constructs.
Fred Drake <fdrake@acm.org>
parents:
9523
diff
changeset
|
1146 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
|
1147 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
|
1148 |
|
8a306dfd9f33
Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff
changeset
|
1149 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
|
1150 |
|
8a306dfd9f33
Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff
changeset
|
1151 |
|
8a306dfd9f33
Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff
changeset
|
1152 \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
|
1153 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
|
1154 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
|
1155 \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
|
1156 \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
|
1157 \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
|
1158 |
|
8a306dfd9f33
Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff
changeset
|
1159 \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
|
1160 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
|
1161 \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
|
1162 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
|
1163 \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
|
1164 |
|
8a306dfd9f33
Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff
changeset
|
1165 \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
|
1166 \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
|
1167 \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
|
1168 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
|
1169 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
|
1170 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
|
1171 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
|
1172 \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
|
1173 \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
|
1174 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
|
1175 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
|
1176 \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
|
1177 |
|
24599
d7ca0a2ce074
Document file.next(). Mark xreadlines obsolete (both method and
Guido van Rossum <guido@python.org>
parents:
24598
diff
changeset
|
1178 \begin{methoddesc}[file]{isatty}{} |
|
d7ca0a2ce074
Document file.next(). Mark xreadlines obsolete (both method and
Guido van Rossum <guido@python.org>
parents:
24598
diff
changeset
|
1179 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
|
1180 \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
|
1181 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
|
1182 \end{methoddesc} |
|
d7ca0a2ce074
Document file.next(). Mark xreadlines obsolete (both method and
Guido van Rossum <guido@python.org>
parents:
24598
diff
changeset
|
1183 |
|
d7ca0a2ce074
Document file.next(). Mark xreadlines obsolete (both method and
Guido van Rossum <guido@python.org>
parents:
24598
diff
changeset
|
1184 \begin{methoddesc}[file]{next}{} |
|
d7ca0a2ce074
Document file.next(). Mark xreadlines obsolete (both method and
Guido van Rossum <guido@python.org>
parents:
24598
diff
changeset
|
1185 A file object is its own iterator, i.e. \code{iter(\var{f})} returns |
|
d7ca0a2ce074
Document file.next(). Mark xreadlines obsolete (both method and
Guido van Rossum <guido@python.org>
parents:
24598
diff
changeset
|
1186 \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
|
1187 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
|
1188 \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
|
1189 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
|
1190 \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
|
1191 \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
|
1192 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
|
1193 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
|
1194 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
|
1195 \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
|
1196 \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
|
1197 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
|
1198 \versionadded{2.3} |
|
d7ca0a2ce074
Document file.next(). Mark xreadlines obsolete (both method and
Guido van Rossum <guido@python.org>
parents:
24598
diff
changeset
|
1199 \end{methoddesc} |
|
d7ca0a2ce074
Document file.next(). Mark xreadlines obsolete (both method and
Guido van Rossum <guido@python.org>
parents:
24598
diff
changeset
|
1200 |
|
8730
8a306dfd9f33
Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff
changeset
|
1201 \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
|
1202 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
|
1203 \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
|
1204 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
|
1205 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
|
1206 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
|
1207 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
|
1208 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
|
1209 C function \cfunction{fread()} more than once in an effort to |
| 26672 | 1210 acquire as close to \var{size} bytes as possible. Also note that |
| 1211 when in non-blocking mode, less data than what was requested may | |
| 1212 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
|
1213 \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
|
1214 |
|
8a306dfd9f33
Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff
changeset
|
1215 \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
|
1216 Read one entire line from the file. A trailing newline character is |
|
10520
7ee1e3134147
Fixed latex2html weirdness with footnotes.
Fred Drake <fdrake@acm.org>
parents:
10241
diff
changeset
|
1217 kept in the string\footnote{ |
|
23860
63ee31bb25f3
Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents:
23847
diff
changeset
|
1218 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
|
1219 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
|
1220 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
|
1221 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
|
1222 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
|
1223 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
|
1224 or not (yes this happens!). |
|
4d14eef8ea07
Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents:
13894
diff
changeset
|
1225 } (but may be absent when a file ends with an |
|
8730
8a306dfd9f33
Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff
changeset
|
1226 incomplete line). If the \var{size} argument is present and |
|
8a306dfd9f33
Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff
changeset
|
1227 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
|
1228 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
|
1229 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
|
1230 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
|
1231 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
|
1232 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
|
1233 \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
|
1234 |
|
8a306dfd9f33
Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff
changeset
|
1235 \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
|
1236 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
|
1237 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
|
1238 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
|
1239 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
|
1240 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
|
1241 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
|
1242 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
|
1243 \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
|
1244 |
|
15926
ac13cef423c8
Document xreadlines() method. (Forgot to check this in before!)
Guido van Rossum <guido@python.org>
parents:
15896
diff
changeset
|
1245 \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
|
1246 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
|
1247 \versionadded{2.1} |
|
24599
d7ca0a2ce074
Document file.next(). Mark xreadlines obsolete (both method and
Guido van Rossum <guido@python.org>
parents:
24598
diff
changeset
|
1248 \deprecated{2.3}{Use \code{for line in file} instead.} |
|
15926
ac13cef423c8
Document xreadlines() method. (Forgot to check this in before!)
Guido van Rossum <guido@python.org>
parents:
15896
diff
changeset
|
1249 \end{methoddesc} |
|
ac13cef423c8
Document xreadlines() method. (Forgot to check this in before!)
Guido van Rossum <guido@python.org>
parents:
15896
diff
changeset
|
1250 |
|
8730
8a306dfd9f33
Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff
changeset
|
1251 \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
|
1252 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
|
1253 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
|
1254 (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
|
1255 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
|
1256 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
|
1257 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
|
1258 \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
|
1259 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
|
1260 this method is essentially a no-op, but it remains useful for files |
|
a06415994cb5
Added information about the interaction of opening a file in append mode
Fred Drake <fdrake@acm.org>
parents:
15522
diff
changeset
|
1261 opened in append mode with reading enabled (mode \code{'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
|
1262 \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
|
1263 |
|
8a306dfd9f33
Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff
changeset
|
1264 \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
|
1265 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
|
1266 \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
|
1267 \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
|
1268 |
|
8a306dfd9f33
Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff
changeset
|
1269 \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
|
1270 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
|
1271 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
|
1272 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
|
1273 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
|
1274 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
|
1275 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
|
1276 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
|
1277 undefined new content. |
|
22214
e24ba04d01b0
file_truncate(): provide full "large file" support on Windows, by
Tim Peters <tim.peters@gmail.com>
parents:
21542
diff
changeset
|
1278 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
|
1279 \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
|
1280 |
|
8a306dfd9f33
Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff
changeset
|
1281 \begin{methoddesc}[file]{write}{str} |
|
20580
376ee174ecd0
Use the \note and \warning macros where appropriate.
Fred Drake <fdrake@acm.org>
parents:
20173
diff
changeset
|
1282 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
|
1283 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
|
1284 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
|
1285 \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
|
1286 |
|
20045
7b8c11739714
Generalize file.writelines() to allow iterable objects.
Tim Peters <tim.peters@gmail.com>
parents:
20031
diff
changeset
|
1287 \begin{methoddesc}[file]{writelines}{sequence} |
|
7b8c11739714
Generalize file.writelines() to allow iterable objects.
Tim Peters <tim.peters@gmail.com>
parents:
20031
diff
changeset
|
1288 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
|
1289 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
|
1290 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
|
1291 (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
|
1292 \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
|
1293 \end{methoddesc} |
|
9e9556924b0a
Added documentation for the xreadlines module & related changes. The
Fred Drake <fdrake@acm.org>
parents:
15731
diff
changeset
|
1294 |
|
8730
8a306dfd9f33
Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff
changeset
|
1295 |
|
20031
e5a3f9d7766b
Note that files are iterable; describe what the iterator returns.
Fred Drake <fdrake@acm.org>
parents:
19529
diff
changeset
|
1296 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
|
1297 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
|
1298 \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
|
1299 |
|
e5a3f9d7766b
Note that files are iterable; describe what the iterator returns.
Fred Drake <fdrake@acm.org>
parents:
19529
diff
changeset
|
1300 |
|
14685
faf3e734254d
Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents:
14557
diff
changeset
|
1301 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
|
1302 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
|
1303 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
|
1304 |
|
8a306dfd9f33
Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff
changeset
|
1305 \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
|
1306 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
|
1307 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
|
1308 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
|
1309 \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
|
1310 |
|
8a306dfd9f33
Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff
changeset
|
1311 \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
|
1312 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
|
1313 \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
|
1314 \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
|
1315 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
|
1316 \end{memberdesc} |
|
8a306dfd9f33
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diff
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|
1317 |
|
8a306dfd9f33
Move files around to get the names to match the module names except for
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diff
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|
1318 \begin{memberdesc}[file]{name} |
|
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Move files around to get the names to match the module names except for
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diff
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|
1319 If the file object was created using \function{open()}, the name of |
|
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Move files around to get the names to match the module names except for
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diff
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|
1320 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>
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diff
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|
1321 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
|
1322 attribute and may not be present on all file-like objects. |
|
8730
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Move files around to get the names to match the module names except for
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|
1323 \end{memberdesc} |
|
8a306dfd9f33
Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
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diff
changeset
|
1324 |
|
8a306dfd9f33
Move files around to get the names to match the module names except for
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diff
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|
1325 \begin{memberdesc}[file]{softspace} |
|
8a306dfd9f33
Move files around to get the names to match the module names except for
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diff
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|
1326 Boolean that indicates whether a space character needs to be printed |
|
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Move files around to get the names to match the module names except for
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parents:
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|
1327 before another value when using the \keyword{print} statement. |
|
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Move files around to get the names to match the module names except for
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diff
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|
1328 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
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diff
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|
1329 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
|
1330 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>
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14044
diff
changeset
|
1331 (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
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|
1332 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>
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14044
diff
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|
1333 \member{softspace} attribute. |
|
20580
376ee174ecd0
Use the \note and \warning macros where appropriate.
Fred Drake <fdrake@acm.org>
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20173
diff
changeset
|
1334 \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
|
1335 \keyword{print} statement, but to allow the implementation of |
|
20580
376ee174ecd0
Use the \note and \warning macros where appropriate.
Fred Drake <fdrake@acm.org>
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diff
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|
1336 \keyword{print} to keep track of its internal state.} |
|
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Move files around to get the names to match the module names except for
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|
1337 \end{memberdesc} |
|
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Move files around to get the names to match the module names except for
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diff
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|
1338 |
|
15383
eeb7c8a5b79f
Document the proper exception to be raised by I/O operations on closed
Fred Drake <fdrake@acm.org>
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15332
diff
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|
1339 |
|
20767
b3f48c5d6e16
Promote file objects out of the "Other Objects" category, so they become
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|
1340 \subsection{Other Built-in Types \label{typesother}} |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1341 |
|
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|
1342 The interpreter supports several other kinds of objects. |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1343 Most of these support only one or two operations. |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1344 |
|
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|
1345 |
|
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Promote file objects out of the "Other Objects" category, so they become
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diff
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|
1346 \subsubsection{Modules \label{typesmodules}} |
|
b3f48c5d6e16
Promote file objects out of the "Other Objects" category, so they become
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|
1347 |
|
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Promote file objects out of the "Other Objects" category, so they become
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diff
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|
1348 The only special operation on a module is attribute access: |
|
b3f48c5d6e16
Promote file objects out of the "Other Objects" category, so they become
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diff
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|
1349 \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
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diff
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|
1350 accesses a name defined in \var{m}'s symbol table. Module attributes |
|
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Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
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diff
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|
1351 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>
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diff
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|
1352 strictly speaking, an operation on a module object; \code{import |
|
b3f48c5d6e16
Promote file objects out of the "Other Objects" category, so they become
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diff
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|
1353 \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>
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diff
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|
1354 rather it requires an (external) \emph{definition} for a module named |
|
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Promote file objects out of the "Other Objects" category, so they become
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diff
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|
1355 \var{foo} somewhere.) |
|
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Promote file objects out of the "Other Objects" category, so they become
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diff
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|
1356 |
|
b3f48c5d6e16
Promote file objects out of the "Other Objects" category, so they become
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diff
changeset
|
1357 A special member of every module is \member{__dict__}. |
|
b3f48c5d6e16
Promote file objects out of the "Other Objects" category, so they become
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diff
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|
1358 This is the dictionary containing the module's symbol table. |
|
b3f48c5d6e16
Promote file objects out of the "Other Objects" category, so they become
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diff
changeset
|
1359 Modifying this dictionary will actually change the module's symbol |
|
b3f48c5d6e16
Promote file objects out of the "Other Objects" category, so they become
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diff
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|
1360 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>
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diff
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|
1361 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>
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diff
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|
1362 defines \code{\var{m}.a} to be \code{1}, but you can't write |
|
b3f48c5d6e16
Promote file objects out of the "Other Objects" category, so they become
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diff
changeset
|
1363 \code{\var{m}.__dict__ = \{\}}. |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1364 |
|
b3f48c5d6e16
Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
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20764
diff
changeset
|
1365 Modules built into the interpreter are written like this: |
|
b3f48c5d6e16
Promote file objects out of the "Other Objects" category, so they become
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diff
changeset
|
1366 \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>
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diff
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|
1367 written as \code{<module 'os' from |
|
b3f48c5d6e16
Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
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diff
changeset
|
1368 '/usr/local/lib/python\shortversion/os.pyc'>}. |
|
b3f48c5d6e16
Promote file objects out of the "Other Objects" category, so they become
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diff
changeset
|
1369 |
|
b3f48c5d6e16
Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
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diff
changeset
|
1370 |
|
b3f48c5d6e16
Promote file objects out of the "Other Objects" category, so they become
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diff
changeset
|
1371 \subsubsection{Classes and Class Instances \label{typesobjects}} |
|
b3f48c5d6e16
Promote file objects out of the "Other Objects" category, so they become
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diff
changeset
|
1372 \nodename{Classes and Instances} |
|
b3f48c5d6e16
Promote file objects out of the "Other Objects" category, so they become
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diff
changeset
|
1373 |
|
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Promote file objects out of the "Other Objects" category, so they become
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diff
changeset
|
1374 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
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|
1375 Reference Manual} for these. |
|
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Promote file objects out of the "Other Objects" category, so they become
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diff
changeset
|
1376 |
|
b3f48c5d6e16
Promote file objects out of the "Other Objects" category, so they become
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diff
changeset
|
1377 |
|
b3f48c5d6e16
Promote file objects out of the "Other Objects" category, so they become
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diff
changeset
|
1378 \subsubsection{Functions \label{typesfunctions}} |
|
b3f48c5d6e16
Promote file objects out of the "Other Objects" category, so they become
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diff
changeset
|
1379 |
|
b3f48c5d6e16
Promote file objects out of the "Other Objects" category, so they become
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diff
changeset
|
1380 Function objects are created by function definitions. The only |
|
b3f48c5d6e16
Promote file objects out of the "Other Objects" category, so they become
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|
1381 operation on a function object is to call it: |
|
b3f48c5d6e16
Promote file objects out of the "Other Objects" category, so they become
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diff
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|
1382 \code{\var{func}(\var{argument-list})}. |
|
b3f48c5d6e16
Promote file objects out of the "Other Objects" category, so they become
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diff
changeset
|
1383 |
|
b3f48c5d6e16
Promote file objects out of the "Other Objects" category, so they become
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diff
changeset
|
1384 There are really two flavors of function objects: built-in functions |
|
b3f48c5d6e16
Promote file objects out of the "Other Objects" category, so they become
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diff
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|
1385 and user-defined functions. Both support the same operation (to call |
|
b3f48c5d6e16
Promote file objects out of the "Other Objects" category, so they become
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diff
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|
1386 the function), but the implementation is different, hence the |
|
b3f48c5d6e16
Promote file objects out of the "Other Objects" category, so they become
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changeset
|
1387 different object types. |
|
b3f48c5d6e16
Promote file objects out of the "Other Objects" category, so they become
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diff
changeset
|
1388 |
|
b3f48c5d6e16
Promote file objects out of the "Other Objects" category, so they become
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diff
changeset
|
1389 The implementation adds two special read-only attributes: |
|
b3f48c5d6e16
Promote file objects out of the "Other Objects" category, so they become
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diff
changeset
|
1390 \code{\var{f}.func_code} is a function's \dfn{code |
|
b3f48c5d6e16
Promote file objects out of the "Other Objects" category, so they become
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diff
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|
1391 object}\obindex{code} (see below) and \code{\var{f}.func_globals} is |
|
b3f48c5d6e16
Promote file objects out of the "Other Objects" category, so they become
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diff
changeset
|
1392 the dictionary used as the function's global namespace (this is the |
|
b3f48c5d6e16
Promote file objects out of the "Other Objects" category, so they become
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diff
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|
1393 same as \code{\var{m}.__dict__} where \var{m} is the module in which |
|
b3f48c5d6e16
Promote file objects out of the "Other Objects" category, so they become
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|
1394 the function \var{f} was defined). |
|
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Promote file objects out of the "Other Objects" category, so they become
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changeset
|
1395 |
|
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diff
changeset
|
1396 Function objects also support getting and setting arbitrary |
|
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Promote file objects out of the "Other Objects" category, so they become
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diff
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|
1397 attributes, which can be used to, e.g. attach metadata to functions. |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1398 Regular attribute dot-notation is used to get and set such |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1399 attributes. \emph{Note that the current implementation only supports |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1400 function attributes on user-defined functions. Function attributes on |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1401 built-in functions may be supported in the future.} |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1402 |
|
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|
1403 Functions have another special attribute \code{\var{f}.__dict__} |
|
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|
1404 (a.k.a. \code{\var{f}.func_dict}) which contains the namespace used to |
|
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|
1405 support function attributes. \code{__dict__} and \code{func_dict} can |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1406 be accessed directly or set to a dictionary object. A function's |
|
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|
1407 dictionary cannot be deleted. |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1408 |
|
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|
1409 \subsubsection{Methods \label{typesmethods}} |
|
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|
1410 \obindex{method} |
|
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|
1411 |
|
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changeset
|
1412 Methods are functions that are called using the attribute notation. |
|
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|
1413 There are two flavors: built-in methods (such as \method{append()} on |
|
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|
1414 lists) and class instance methods. Built-in methods are described |
|
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|
1415 with the types that support them. |
|
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|
1416 |
|
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|
1417 The implementation adds two special read-only attributes to class |
|
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|
1418 instance methods: \code{\var{m}.im_self} is the object on which the |
|
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|
1419 method operates, and \code{\var{m}.im_func} is the function |
|
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|
1420 implementing the method. Calling \code{\var{m}(\var{arg-1}, |
|
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|
1421 \var{arg-2}, \textrm{\ldots}, \var{arg-n})} is completely equivalent to |
|
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|
1422 calling \code{\var{m}.im_func(\var{m}.im_self, \var{arg-1}, |
|
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|
1423 \var{arg-2}, \textrm{\ldots}, \var{arg-n})}. |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1424 |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1425 Class instance methods are either \emph{bound} or \emph{unbound}, |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1426 referring to whether the method was accessed through an instance or a |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1427 class, respectively. When a method is unbound, its \code{im_self} |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1428 attribute will be \code{None} and if called, an explicit \code{self} |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1429 object must be passed as the first argument. In this case, |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1430 \code{self} must be an instance of the unbound method's class (or a |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1431 subclass of that class), otherwise a \code{TypeError} is raised. |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1432 |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1433 Like function objects, methods objects support getting |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1434 arbitrary attributes. However, since method attributes are actually |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1435 stored on the underlying function object (\code{meth.im_func}), |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1436 setting method attributes on either bound or unbound methods is |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1437 disallowed. Attempting to set a method attribute results in a |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1438 \code{TypeError} being raised. In order to set a method attribute, |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1439 you need to explicitly set it on the underlying function object: |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1440 |
|
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|
1441 \begin{verbatim} |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1442 class C: |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1443 def method(self): |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1444 pass |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1445 |
|
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|
1446 c = C() |
|
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|
1447 c.method.im_func.whoami = 'my name is c' |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1448 \end{verbatim} |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1449 |
|
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|
1450 See the \citetitle[../ref/ref.html]{Python Reference Manual} for more |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1451 information. |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1452 |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1453 |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1454 \subsubsection{Code Objects \label{bltin-code-objects}} |
|
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|
1455 \obindex{code} |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1456 |
|
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|
1457 Code objects are used by the implementation to represent |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1458 ``pseudo-compiled'' executable Python code such as a function body. |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1459 They differ from function objects because they don't contain a |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1460 reference to their global execution environment. Code objects are |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1461 returned by the built-in \function{compile()} function and can be |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1462 extracted from function objects through their \member{func_code} |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1463 attribute. |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1464 \bifuncindex{compile} |
|
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|
1465 \withsubitem{(function object attribute)}{\ttindex{func_code}} |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1466 |
|
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|
1467 A code object can be executed or evaluated by passing it (instead of a |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1468 source string) to the \keyword{exec} statement or the built-in |
|
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|
1469 \function{eval()} function. |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1470 \stindex{exec} |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1471 \bifuncindex{eval} |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1472 |
|
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|
1473 See the \citetitle[../ref/ref.html]{Python Reference Manual} for more |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1474 information. |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1475 |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1476 |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1477 \subsubsection{Type Objects \label{bltin-type-objects}} |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1478 |
|
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|
1479 Type objects represent the various object types. An object's type is |
|
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|
1480 accessed by the built-in function \function{type()}. There are no special |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1481 operations on types. The standard module \module{types} defines names |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1482 for all standard built-in types. |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1483 \bifuncindex{type} |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1484 \refstmodindex{types} |
|
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|
1485 |
|
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|
1486 Types are written like this: \code{<type 'int'>}. |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1487 |
|
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|
1488 |
|
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|
1489 \subsubsection{The Null Object \label{bltin-null-object}} |
|
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|
1490 |
|
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|
1491 This object is returned by functions that don't explicitly return a |
|
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Promote file objects out of the "Other Objects" category, so they become
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|
1492 value. It supports no special operations. There is exactly one null |
|
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|
1493 object, named \code{None} (a built-in name). |
|
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|
1494 |
|
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|
1495 It is written as \code{None}. |
|
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|
1496 |
|
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|
1497 |
|
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|
1498 \subsubsection{The Ellipsis Object \label{bltin-ellipsis-object}} |
|
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|
1499 |
|
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|
1500 This object is used by extended slice notation (see the |
|
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|
1501 \citetitle[../ref/ref.html]{Python Reference Manual}). It supports no |
|
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|
1502 special operations. There is exactly one ellipsis object, named |
|
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|
1503 \constant{Ellipsis} (a built-in name). |
|
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|
1504 |
|
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|
1505 It is written as \code{Ellipsis}. |
|
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|
1506 |
|
22785
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|
1507 \subsubsection{Boolean Values} |
|
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|
1508 |
|
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|
1509 Boolean values are the two constant objects \code{False} and |
|
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|
1510 \code{True}. They are used to represent truth values (although other |
|
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|
1511 values can also be considered false or true). In numeric contexts |
|
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|
1512 (for example when used as the argument to an arithmetic operator), |
|
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|
1513 they behave like the integers 0 and 1, respectively. The built-in |
|
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|
1514 function \function{bool()} can be used to cast any value to a Boolean, |
|
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|
1515 if the value can be interpreted as a truth value (see section Truth |
|
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|
1516 Value Testing above). |
|
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|
1517 |
|
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|
1518 They are written as \code{False} and \code{True}, respectively. |
|
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|
1519 \index{False} |
|
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|
1520 \index{True} |
|
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|
1521 \indexii{Boolean}{values} |
|
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|
1522 |
|
20767
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|
1523 |
|
10156
0f7d694bc334
Make sure all HTML pages generated from this section have reasonable
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10147
diff
changeset
|
1524 \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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|
1525 |
|
11463
17e12305973e
Use \citetitle and \programopt as appropriate.
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11183
diff
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|
1526 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()
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13967
diff
changeset
|
1527 information. It describes stack frame objects, traceback objects, and |
|
a905c5aa0691
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1528 slice objects. |
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1529 |
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1530 |
| 9083 | 1531 \subsection{Special Attributes \label{specialattrs}} |
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1532 |
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1533 The implementation adds a few special read-only attributes to several |
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1534 object types, where they are relevant: |
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1535 |
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1536 \begin{memberdesc}[object]{__dict__} |
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1537 A dictionary or other mapping object used to store an |
| 9083 | 1538 object's (writable) attributes. |
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1539 \end{memberdesc} |
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1540 |
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1541 \begin{memberdesc}[object]{__methods__} |
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1542 \deprecated{2.2}{Use the built-in function \function{dir()} to get a |
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1543 list of an object's attributes. This attribute is no longer available.} |
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1544 \end{memberdesc} |
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1545 |
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1546 \begin{memberdesc}[object]{__members__} |
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1547 \deprecated{2.2}{Use the built-in function \function{dir()} to get a |
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1548 list of an object's attributes. This attribute is no longer available.} |
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1549 \end{memberdesc} |
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1550 |
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1551 \begin{memberdesc}[instance]{__class__} |
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1552 The class to which a class instance belongs. |
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1553 \end{memberdesc} |
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1554 |
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1555 \begin{memberdesc}[class]{__bases__} |
|
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1556 The tuple of base classes of a class object. If there are no base |
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1557 classes, this will be an empty tuple. |
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1558 \end{memberdesc} |
