cpython-lru_cache-weakref: Doc/lib/libstdtypes.tex annotate

annotate Doc/lib/libstdtypes.tex @ 8730:8a306dfd9f33 legacy-trunk

Move files around to get the names to match the module names except for case. Two modules (SocketServer, BaseHTTPServer) still don't match; those names are just too long!

author	Fred Drake <fdrake@acm.org>
date	Fri, 24 Jul 1998 13:56:11 +0000
parents
children	ddaac06ec326

rev	line source
8730 8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	1 \section{Built-in Types}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	2 \label{types}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	3
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	4 The following sections describe the standard types that are built into
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	5 the interpreter. These are the numeric types, sequence types, and
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	6 several others, including types themselves. There is no explicit
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	7 Boolean type; use integers instead.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	8 \indexii{built-in}{types}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	9 \indexii{Boolean}{type}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	10
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	11 Some operations are supported by several object types; in particular,
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	12 all objects can be compared, tested for truth value, and converted to
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	13 a string (with the \code{`{\rm \ldots}`} notation). The latter conversion is
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	14 implicitly used when an object is written by the \code{print} statement.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	15 \stindex{print}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	16
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	17
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	18 \subsection{Truth Value Testing}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	19 \label{truth}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	20
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	21 Any object can be tested for truth value, for use in an \code{if} or
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	22 \code{while} condition or as operand of the Boolean operations below.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	23 The following values are considered false:
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	24 \stindex{if}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	25 \stindex{while}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	26 \indexii{truth}{value}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	27 \indexii{Boolean}{operations}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	28 \index{false}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	29
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	30 \setindexsubitem{(Built-in object)}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	31 \begin{itemize}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	32
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	33 \item \code{None}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	34 \ttindex{None}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	35
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	36 \item zero of any numeric type, e.g., \code{0}, \code{0L}, \code{0.0}.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	37
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	38 \item any empty sequence, e.g., \code{''}, \code{()}, \code{[]}.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	39
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	40 \item any empty mapping, e.g., \code{\{\}}.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	41
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	42 \item instances of user-defined classes, if the class defines a
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	43 \code{__nonzero__()} or \code{__len__()} method, when that
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	44 method returns zero.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	45
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	46 \end{itemize}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	47
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	48 All other values are considered true --- so objects of many types are
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	49 always true.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	50 \index{true}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	51
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	52 Operations and built-in functions that have a Boolean result always
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	53 return \code{0} for false and \code{1} for true, unless otherwise
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	54 stated. (Important exception: the Boolean operations
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	55 \samp{or}\opindex{or} and \samp{and}\opindex{and} always return one of
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	56 their operands.)
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	57
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	58
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	59 \subsection{Boolean Operations}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	60 \label{boolean}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	61
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	62 These are the Boolean operations, ordered by ascending priority:
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	63 \indexii{Boolean}{operations}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	64
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	65 \begin{tableiii}{c\|l\|c}{code}{Operation}{Result}{Notes}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	66 \lineiii{\var{x} or \var{y}}{if \var{x} is false, then \var{y}, else \var{x}}{(1)}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	67 \lineiii{\var{x} and \var{y}}{if \var{x} is false, then \var{x}, else \var{y}}{(1)}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	68 \hline
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	69 \lineiii{not \var{x}}{if \var{x} is false, then \code{1}, else \code{0}}{(2)}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	70 \end{tableiii}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	71 \opindex{and}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	72 \opindex{or}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	73 \opindex{not}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	74
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	75 \noindent
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	76 Notes:
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	77
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	78 \begin{description}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	79
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	80 \item[(1)]
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	81 These only evaluate their second argument if needed for their outcome.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	82
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	83 \item[(2)]
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	84 \samp{not} has a lower priority than non-Boolean operators, so e.g.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	85 \code{not a == b} is interpreted as \code{not(a == b)}, and
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	86 \code{a == not b} is a syntax error.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	87
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	88 \end{description}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	89
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	90
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	91 \subsection{Comparisons}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	92 \label{comparisons}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	93
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	94 Comparison operations are supported by all objects. They all have the
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	95 same priority (which is higher than that of the Boolean operations).
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	96 Comparisons can be chained arbitrarily, e.g. \code{x < y <= z} is
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	97 equivalent to \code{x < y and y <= z}, except that \code{y} is
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	98 evaluated only once (but in both cases \code{z} is not evaluated at
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	99 all when \code{x < y} is found to be false).
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	100 \indexii{chaining}{comparisons}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	101
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	102 This table summarizes the comparison operations:
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	103
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	104 \begin{tableiii}{c\|l\|c}{code}{Operation}{Meaning}{Notes}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	105 \lineiii{<}{strictly less than}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	106 \lineiii{<=}{less than or equal}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	107 \lineiii{>}{strictly greater than}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	108 \lineiii{>=}{greater than or equal}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	109 \lineiii{==}{equal}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	110 \lineiii{<>}{not equal}{(1)}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	111 \lineiii{!=}{not equal}{(1)}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	112 \lineiii{is}{object identity}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	113 \lineiii{is not}{negated object identity}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	114 \end{tableiii}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	115 \indexii{operator}{comparison}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	116 \opindex{==} % XXX All others have funny characters < ! >
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	117 \opindex{is}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	118 \opindex{is not}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	119
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	120 \noindent
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	121 Notes:
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	122
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	123 \begin{description}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	124
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	125 \item[(1)]
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	126 \code{<>} and \code{!=} are alternate spellings for the same operator.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	127 (I couldn't choose between \ABC{} and \C{}! :-)
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	128 \index{ABC language@\ABC{} language}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	129 \index{language!ABC@\ABC{}}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	130 \indexii{C@\C{}}{language}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	131
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	132 \end{description}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	133
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	134 Objects of different types, except different numeric types, never
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	135 compare equal; such objects are ordered consistently but arbitrarily
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	136 (so that sorting a heterogeneous array yields a consistent result).
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	137 Furthermore, some types (e.g., windows) support only a degenerate
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	138 notion of comparison where any two objects of that type are unequal.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	139 Again, such objects are ordered arbitrarily but consistently.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	140 \indexii{types}{numeric}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	141 \indexii{objects}{comparing}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	142
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	143 (Implementation note: objects of different types except numbers are
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	144 ordered by their type names; objects of the same types that don't
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	145 support proper comparison are ordered by their address.)
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	146
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	147 Two more operations with the same syntactic priority, \samp{in} and
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	148 \samp{not in}, are supported only by sequence types (below).
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	149 \opindex{in}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	150 \opindex{not in}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	151
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	152
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	153 \subsection{Numeric Types}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	154 \label{typesnumeric}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	155
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	156 There are four numeric types: \dfn{plain integers}, \dfn{long integers},
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	157 \dfn{floating point numbers}, and \dfn{complex numbers}.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	158 Plain integers (also just called \dfn{integers})
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	159 are implemented using \code{long} in \C{}, which gives them at least 32
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	160 bits of precision. Long integers have unlimited precision. Floating
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	161 point numbers are implemented using \code{double} in \C{}. All bets on
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	162 their precision are off unless you happen to know the machine you are
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	163 working with.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	164 \indexii{numeric}{types}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	165 \indexii{integer}{types}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	166 \indexii{integer}{type}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	167 \indexiii{long}{integer}{type}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	168 \indexii{floating point}{type}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	169 \indexii{complex number}{type}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	170 \indexii{C@\C{}}{language}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	171
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	172 Complex numbers have a real and imaginary part, which are both
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	173 implemented using \code{double} in \C{}. To extract these parts from
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	174 a complex number \var{z}, use \code{\var{z}.real} and \code{\var{z}.imag}.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	175
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	176 Numbers are created by numeric literals or as the result of built-in
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	177 functions and operators. Unadorned integer literals (including hex
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	178 and octal numbers) yield plain integers. Integer literals with an \samp{L}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	179 or \samp{l} suffix yield long integers
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	180 (\samp{L} is preferred because \samp{1l} looks too much like eleven!).
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	181 Numeric literals containing a decimal point or an exponent sign yield
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	182 floating point numbers. Appending \samp{j} or \samp{J} to a numeric
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	183 literal yields a complex number.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	184 \indexii{numeric}{literals}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	185 \indexii{integer}{literals}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	186 \indexiii{long}{integer}{literals}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	187 \indexii{floating point}{literals}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	188 \indexii{complex number}{literals}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	189 \indexii{hexadecimal}{literals}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	190 \indexii{octal}{literals}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	191
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	192 Python fully supports mixed arithmetic: when a binary arithmetic
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	193 operator has operands of different numeric types, the operand with the
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	194 ``smaller'' type is converted to that of the other, where plain
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	195 integer is smaller than long integer is smaller than floating point is
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	196 smaller than complex.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	197 Comparisons between numbers of mixed type use the same rule.%
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	198 \footnote{As a consequence, the list \code{[1, 2]} is considered equal
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	199 to \code{[1.0, 2.0]}, and similar for tuples.}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	200 The functions \code{int()}, \code{long()}, \code{float()},
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	201 and \code{complex()} can be used
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	202 to coerce numbers to a specific type.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	203 \index{arithmetic}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	204 \bifuncindex{int}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	205 \bifuncindex{long}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	206 \bifuncindex{float}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	207 \bifuncindex{complex}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	208
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	209 All numeric types support the following operations, sorted by
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	210 ascending priority (operations in the same box have the same
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	211 priority; all numeric operations have a higher priority than
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	212 comparison operations):
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	213
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	214 \begin{tableiii}{c\|l\|c}{code}{Operation}{Result}{Notes}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	215 \lineiii{\var{x} + \var{y}}{sum of \var{x} and \var{y}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	216 \lineiii{\var{x} - \var{y}}{difference of \var{x} and \var{y}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	217 \hline
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	218 \lineiii{\var{x} * \var{y}}{product of \var{x} and \var{y}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	219 \lineiii{\var{x} / \var{y}}{quotient of \var{x} and \var{y}}{(1)}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	220 \lineiii{\var{x} \%{} \var{y}}{remainder of \code{\var{x} / \var{y}}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	221 \hline
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	222 \lineiii{-\var{x}}{\var{x} negated}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	223 \lineiii{+\var{x}}{\var{x} unchanged}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	224 \hline
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	225 \lineiii{abs(\var{x})}{absolute value or magnitude of \var{x}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	226 \lineiii{int(\var{x})}{\var{x} converted to integer}{(2)}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	227 \lineiii{long(\var{x})}{\var{x} converted to long integer}{(2)}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	228 \lineiii{float(\var{x})}{\var{x} converted to floating point}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	229 \lineiii{complex(\var{re},\var{im})}{a complex number with real part \var{re}, imaginary part \var{im}. \var{im} defaults to zero.}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	230 \lineiii{divmod(\var{x}, \var{y})}{the pair \code{(\var{x} / \var{y}, \var{x} \%{} \var{y})}}{(3)}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	231 \lineiii{pow(\var{x}, \var{y})}{\var{x} to the power \var{y}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	232 \lineiii{\var{x} ** \var{y}}{\var{x} to the power \var{y}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	233 \end{tableiii}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	234 \indexiii{operations on}{numeric}{types}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	235
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	236 \noindent
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	237 Notes:
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	238 \begin{description}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	239
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	240 \item[(1)]
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	241 For (plain or long) integer division, the result is an integer.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	242 The result is always rounded towards minus infinity: 1/2 is 0,
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	243 (-1)/2 is -1, 1/(-2) is -1, and (-1)/(-2) is 0.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	244 \indexii{integer}{division}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	245 \indexiii{long}{integer}{division}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	246
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	247 \item[(2)]
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	248 Conversion from floating point to (long or plain) integer may round or
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	249 truncate as in \C{}; see functions \code{floor()} and \code{ceil()} in
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	250 module \code{math} for well-defined conversions.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	251 \bifuncindex{floor}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	252 \bifuncindex{ceil}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	253 \indexii{numeric}{conversions}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	254 \refbimodindex{math}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	255 \indexii{C@\C{}}{language}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	256
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	257 \item[(3)]
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	258 See the section on built-in functions for an exact definition.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	259
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	260 \end{description}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	261 % XXXJH exceptions: overflow (when? what operations?) zerodivision
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	262
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	263 \subsubsection{Bit-string Operations on Integer Types}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	264 \nodename{Bit-string Operations}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	265
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	266 Plain and long integer types support additional operations that make
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	267 sense only for bit-strings. Negative numbers are treated as their 2's
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	268 complement value (for long integers, this assumes a sufficiently large
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	269 number of bits that no overflow occurs during the operation).
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	270
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	271 The priorities of the binary bit-wise operations are all lower than
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	272 the numeric operations and higher than the comparisons; the unary
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	273 operation \samp{\~} has the same priority as the other unary numeric
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	274 operations (\samp{+} and \samp{-}).
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	275
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	276 This table lists the bit-string operations sorted in ascending
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	277 priority (operations in the same box have the same priority):
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	278
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	279 \begin{tableiii}{c\|l\|c}{code}{Operation}{Result}{Notes}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	280 \lineiii{\var{x} \| \var{y}}{bitwise \dfn{or} of \var{x} and \var{y}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	281 \lineiii{\var{x} \^{} \var{y}}{bitwise \dfn{exclusive or} of \var{x} and \var{y}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	282 \lineiii{\var{x} \&{} \var{y}}{bitwise \dfn{and} of \var{x} and \var{y}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	283 \lineiii{\var{x} << \var{n}}{\var{x} shifted left by \var{n} bits}{(1), (2)}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	284 \lineiii{\var{x} >> \var{n}}{\var{x} shifted right by \var{n} bits}{(1), (3)}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	285 \hline
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	286 \lineiii{\~\var{x}}{the bits of \var{x} inverted}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	287 \end{tableiii}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	288 \indexiii{operations on}{integer}{types}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	289 \indexii{bit-string}{operations}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	290 \indexii{shifting}{operations}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	291 \indexii{masking}{operations}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	292
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	293 \noindent
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	294 Notes:
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	295 \begin{description}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	296 \item[(1)] Negative shift counts are illegal and cause a
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	297 \exception{ValueError} to be raised.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	298 \item[(2)] A left shift by \var{n} bits is equivalent to
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	299 multiplication by \code{pow(2, \var{n})} without overflow check.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	300 \item[(3)] A right shift by \var{n} bits is equivalent to
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	301 division by \code{pow(2, \var{n})} without overflow check.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	302 \end{description}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	303
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	304
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	305 \subsection{Sequence Types}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	306 \label{typesseq}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	307
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	308 There are three sequence types: strings, lists and tuples.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	309
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	310 Strings literals are written in single or double quotes:
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	311 \code{'xyzzy'}, \code{"frobozz"}. See Chapter 2 of the \emph{Python
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	312 Reference Manual} for more about string literals. Lists are
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	313 constructed with square brackets, separating items with commas:
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	314 \code{[a, b, c]}. Tuples are constructed by the comma operator (not
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	315 within square brackets), with or without enclosing parentheses, but an
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	316 empty tuple must have the enclosing parentheses, e.g.,
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	317 \code{a, b, c} or \code{()}. A single item tuple must have a trailing
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	318 comma, e.g., \code{(d,)}.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	319 \indexii{sequence}{types}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	320 \indexii{string}{type}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	321 \indexii{tuple}{type}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	322 \indexii{list}{type}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	323
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	324 Sequence types support the following operations. The \samp{in} and
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	325 \samp{not in} operations have the same priorities as the comparison
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	326 operations. The \samp{+} and \samp{*} operations have the same
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	327 priority as the corresponding numeric operations.\footnote{They must
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	328 have since the parser can't tell the type of the operands.}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	329
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	330 This table lists the sequence operations sorted in ascending priority
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	331 (operations in the same box have the same priority). In the table,
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	332 \var{s} and \var{t} are sequences of the same type; \var{n}, \var{i}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	333 and \var{j} are integers:
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	334
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	335 \begin{tableiii}{c\|l\|c}{code}{Operation}{Result}{Notes}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	336 \lineiii{\var{x} in \var{s}}{\code{1} if an item of \var{s} is equal to \var{x}, else \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	337 \lineiii{\var{x} not in \var{s}}{\code{0} if an item of \var{s} is
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	338 equal to \var{x}, else \code{1}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	339 \hline
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	340 \lineiii{\var{s} + \var{t}}{the concatenation of \var{s} and \var{t}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	341 \lineiii{\var{s} * \var{n}{\rm ,} \var{n} * \var{s}}{\var{n} copies of \var{s} concatenated}{(3)}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	342 \hline
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	343 \lineiii{\var{s}[\var{i}]}{\var{i}'th item of \var{s}, origin 0}{(1)}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	344 \lineiii{\var{s}[\var{i}:\var{j}]}{slice of \var{s} from \var{i} to \var{j}}{(1), (2)}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	345 \hline
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	346 \lineiii{len(\var{s})}{length of \var{s}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	347 \lineiii{min(\var{s})}{smallest item of \var{s}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	348 \lineiii{max(\var{s})}{largest item of \var{s}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	349 \end{tableiii}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	350 \indexiii{operations on}{sequence}{types}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	351 \bifuncindex{len}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	352 \bifuncindex{min}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	353 \bifuncindex{max}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	354 \indexii{concatenation}{operation}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	355 \indexii{repetition}{operation}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	356 \indexii{subscript}{operation}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	357 \indexii{slice}{operation}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	358 \opindex{in}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	359 \opindex{not in}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	360
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	361 \noindent
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	362 Notes:
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	363
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	364 \begin{description}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	365
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	366 \item[(1)] If \var{i} or \var{j} is negative, the index is relative to
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	367 the end of the string, i.e., \code{len(\var{s}) + \var{i}} or
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	368 \code{len(\var{s}) + \var{j}} is substituted. But note that \code{-0} is
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	369 still \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	370
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	371 \item[(2)] The slice of \var{s} from \var{i} to \var{j} is defined as
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	372 the sequence of items with index \var{k} such that \code{\var{i} <=
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	373 \var{k} < \var{j}}. If \var{i} or \var{j} is greater than
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	374 \code{len(\var{s})}, use \code{len(\var{s})}. If \var{i} is omitted,
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	375 use \code{0}. If \var{j} is omitted, use \code{len(\var{s})}. If
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	376 \var{i} is greater than or equal to \var{j}, the slice is empty.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	377
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	378 \item[(3)] Values of \var{n} less than \code{0} are treated as
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	379 \code{0} (which yields an empty sequence of the same type as
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	380 \var{s}).
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	381
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	382 \end{description}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	383
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	384 \subsubsection{More String Operations}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	385
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	386 String objects have one unique built-in operation: the \code{\%}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	387 operator (modulo) with a string left argument interprets this string
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	388 as a \C{} \cfunction{sprintf()} format string to be applied to the
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	389 right argument, and returns the string resulting from this formatting
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	390 operation.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	391
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	392 The right argument should be a tuple with one item for each argument
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	393 required by the format string; if the string requires a single
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	394 argument, the right argument may also be a single non-tuple object.%
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	395 \footnote{A tuple object in this case should be a singleton.}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	396 The following format characters are understood:
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	397 \code{\%}, \code{c}, \code{s}, \code{i}, \code{d}, \code{u}, \code{o},
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	398 \code{x}, \code{X}, \code{e}, \code{E}, \code{f}, \code{g}, \code{G}.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	399 Width and precision may be a \code{*} to specify that an integer argument
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	400 specifies the actual width or precision. The flag characters
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	401 \code{-}, \code{+}, blank, \code{\#} and \code{0} are understood. The
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	402 size specifiers \code{h}, \code{l} or \code{L} may be
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	403 present but are ignored. The \code{\%s} conversion takes any Python
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	404 object and converts it to a string using \code{str()} before
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	405 formatting it. The ANSI features \code{\%p} and \code{\%n}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	406 are not supported. Since Python strings have an explicit length,
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	407 \code{\%s} conversions don't assume that \code{'\e0'} is the end of
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	408 the string.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	409
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	410 For safety reasons, floating point precisions are clipped to 50;
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	411 \code{\%f} conversions for numbers whose absolute value is over 1e25
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	412 are replaced by \code{\%g} conversions.%
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	413 \footnote{These numbers are fairly arbitrary. They are intended to
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	414 avoid printing endless strings of meaningless digits without hampering
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	415 correct use and without having to know the exact precision of floating
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	416 point values on a particular machine.}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	417 All other errors raise exceptions.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	418
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	419 If the right argument is a dictionary (or any kind of mapping), then
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	420 the formats in the string must have a parenthesized key into that
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	421 dictionary inserted immediately after the \character{\%} character,
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	422 and each format formats the corresponding entry from the mapping.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	423 For example:
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	424
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	425 \begin{verbatim}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	426 >>> count = 2
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	427 >>> language = 'Python'
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	428 >>> print '%(language)s has %(count)03d quote types.' % vars()
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	429 Python has 002 quote types.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	430 \end{verbatim}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	431
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	432 In this case no \code{*} specifiers may occur in a format (since they
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	433 require a sequential parameter list).
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	434
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	435 Additional string operations are defined in standard module
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	436 \module{string} and in built-in module \module{re}.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	437 \refstmodindex{string}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	438 \refbimodindex{re}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	439
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	440 \subsubsection{Mutable Sequence Types}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	441
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	442 List objects support additional operations that allow in-place
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	443 modification of the object.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	444 These operations would be supported by other mutable sequence types
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	445 (when added to the language) as well.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	446 Strings and tuples are immutable sequence types and such objects cannot
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	447 be modified once created.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	448 The following operations are defined on mutable sequence types (where
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	449 \var{x} is an arbitrary object):
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	450 \indexiii{mutable}{sequence}{types}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	451 \indexii{list}{type}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	452
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	453 \begin{tableiii}{c\|l\|c}{code}{Operation}{Result}{Notes}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	454 \lineiii{\var{s}[\var{i}] = \var{x}}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	455 {item \var{i} of \var{s} is replaced by \var{x}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	456 \lineiii{\var{s}[\var{i}:\var{j}] = \var{t}}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	457 {slice of \var{s} from \var{i} to \var{j} is replaced by \var{t}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	458 \lineiii{del \var{s}[\var{i}:\var{j}]}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	459 {same as \code{\var{s}[\var{i}:\var{j}] = []}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	460 \lineiii{\var{s}.append(\var{x})}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	461 {same as \code{\var{s}[len(\var{s}):len(\var{s})] = [\var{x}]}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	462 \lineiii{\var{s}.count(\var{x})}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	463 {return number of \var{i}'s for which \code{\var{s}[\var{i}] == \var{x}}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	464 \lineiii{\var{s}.index(\var{x})}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	465 {return smallest \var{i} such that \code{\var{s}[\var{i}] == \var{x}}}{(1)}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	466 \lineiii{\var{s}.insert(\var{i}, \var{x})}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	467 {same as \code{\var{s}[\var{i}:\var{i}] = [\var{x}]}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	468 if \code{\var{i} >= 0}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	469 \lineiii{\var{s}.pop(\optional{\var{i}})}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	470 {same as \code{\var{x} = \var{s}[\var{i}]; del \var{s}[\var{i}]; return \var{x}}}{(4)}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	471 \lineiii{\var{s}.remove(\var{x})}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	472 {same as \code{del \var{s}[\var{s}.index(\var{x})]}}{(1)}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	473 \lineiii{\var{s}.reverse()}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	474 {reverses the items of \var{s} in place}{(3)}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	475 \lineiii{\var{s}.sort(\optional{\var{cmpfunc}})}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	476 {sort the items of \var{s} in place}{(2), (3)}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	477 \end{tableiii}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	478 \indexiv{operations on}{mutable}{sequence}{types}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	479 \indexiii{operations on}{sequence}{types}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	480 \indexiii{operations on}{list}{type}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	481 \indexii{subscript}{assignment}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	482 \indexii{slice}{assignment}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	483 \stindex{del}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	484 \setindexsubitem{(list method)}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	485 \ttindex{append}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	486 \ttindex{count}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	487 \ttindex{index}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	488 \ttindex{insert}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	489 \ttindex{pop}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	490 \ttindex{remove}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	491 \ttindex{reverse}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	492 \ttindex{sort}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	493
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	494 \noindent
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	495 Notes:
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	496 \begin{description}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	497 \item[(1)] Raises an exception when \var{x} is not found in \var{s}.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	498
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	499 \item[(2)] The \code{sort()} method takes an optional argument
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	500 specifying a comparison function of two arguments (list items) which
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	501 should return \code{-1}, \code{0} or \code{1} depending on whether the
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	502 first argument is considered smaller than, equal to, or larger than the
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	503 second argument. Note that this slows the sorting process down
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	504 considerably; e.g. to sort a list in reverse order it is much faster
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	505 to use calls to \code{sort()} and \code{reverse()} than to use
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	506 \code{sort()} with a comparison function that reverses the ordering of
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	507 the elements.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	508
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	509 \item[(3)] The \code{sort()} and \code{reverse()} methods modify the
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	510 list in place for economy of space when sorting or reversing a large
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	511 list. They don't return the sorted or reversed list to remind you of
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	512 this side effect.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	513
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	514 \item[(4)] The \method{pop()} method is experimental and not supported
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	515 by other mutable sequence types than lists.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	516 The optional argument \var{i} defaults to \code{-1}, so that
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	517 by default the last item is removed and returned.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	518
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	519 \end{description}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	520
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	521
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	522 \subsection{Mapping Types}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	523 \label{typesmapping}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	524
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	525 A \dfn{mapping} object maps values of one type (the key type) to
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	526 arbitrary objects. Mappings are mutable objects. There is currently
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	527 only one standard mapping type, the \dfn{dictionary}. A dictionary's keys are
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	528 almost arbitrary values. The only types of values not acceptable as
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	529 keys are values containing lists or dictionaries or other mutable
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	530 types that are compared by value rather than by object identity.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	531 Numeric types used for keys obey the normal rules for numeric
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	532 comparison: if two numbers compare equal (e.g. \code{1} and
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	533 \code{1.0}) then they can be used interchangeably to index the same
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	534 dictionary entry.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	535
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	536 \indexii{mapping}{types}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	537 \indexii{dictionary}{type}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	538
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	539 Dictionaries are created by placing a comma-separated list of
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	540 \code{\var{key}: \var{value}} pairs within braces, for example:
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	541 \code{\{'jack': 4098, 'sjoerd': 4127\}} or
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	542 \code{\{4098: 'jack', 4127: 'sjoerd'\}}.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	543
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	544 The following operations are defined on mappings (where \var{a} is a
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	545 mapping, \var{k} is a key and \var{x} is an arbitrary object):
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	546
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	547 \begin{tableiii}{c\|l\|c}{code}{Operation}{Result}{Notes}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	548 \lineiii{len(\var{a})}{the number of items in \var{a}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	549 \lineiii{\var{a}[\var{k}]}{the item of \var{a} with key \var{k}}{(1)}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	550 \lineiii{\var{a}[\var{k}] = \var{x}}{set \code{\var{a}[\var{k}]} to \var{x}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	551 \lineiii{del \var{a}[\var{k}]}{remove \code{\var{a}[\var{k}]} from \var{a}}{(1)}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	552 \lineiii{\var{a}.clear()}{remove all items from \code{a}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	553 \lineiii{\var{a}.copy()}{a (shallow) copy of \code{a}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	554 \lineiii{\var{a}.has_key(\var{k})}{\code{1} if \var{a} has a key \var{k}, else \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	555 \lineiii{\var{a}.items()}{a copy of \var{a}'s list of (key, item) pairs}{(2)}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	556 \lineiii{\var{a}.keys()}{a copy of \var{a}'s list of keys}{(2)}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	557 \lineiii{\var{a}.update(\var{b})}{\code{for k, v in \var{b}.items(): \var{a}[k] = v}}{(3)}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	558 \lineiii{\var{a}.values()}{a copy of \var{a}'s list of values}{(2)}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	559 \lineiii{\var{a}.get(\var{k}\optional{, \var{f}})}{the item of \var{a} with key \var{k}}{(4)}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	560 \end{tableiii}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	561 \indexiii{operations on}{mapping}{types}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	562 \indexiii{operations on}{dictionary}{type}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	563 \stindex{del}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	564 \bifuncindex{len}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	565 \setindexsubitem{(dictionary method)}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	566 \ttindex{keys}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	567 \ttindex{has_key}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	568
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	569 \noindent
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	570 Notes:
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	571 \begin{description}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	572 \item[(1)] Raises an exception if \var{k} is not in the map.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	573
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	574 \item[(2)] Keys and values are listed in random order.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	575
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	576 \item[(3)] \var{b} must be of the same type as \var{a}.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	577
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	578 \item[(4)] Never raises an exception if \var{k} is not in the map,
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	579 instead it returns \var{f}. \var{f} is optional, when not provided
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	580 and \var{k} is not in the map, \code{None} is returned.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	581 \end{description}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	582
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	583
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	584 \subsection{Other Built-in Types}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	585 \label{typesother}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	586
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	587 The interpreter supports several other kinds of objects.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	588 Most of these support only one or two operations.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	589
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	590 \subsubsection{Modules}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	591
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	592 The only special operation on a module is attribute access:
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	593 \code{\var{m}.\var{name}}, where \var{m} is a module and \var{name}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	594 accesses a name defined in \var{m}'s symbol table. Module attributes
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	595 can be assigned to. (Note that the \code{import} statement is not,
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	596 strictly spoking, an operation on a module object; \code{import
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	597 \var{foo}} does not require a module object named \var{foo} to exist,
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	598 rather it requires an (external) \emph{definition} for a module named
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	599 \var{foo} somewhere.)
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	600
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	601 A special member of every module is \code{__dict__}.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	602 This is the dictionary containing the module's symbol table.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	603 Modifying this dictionary will actually change the module's symbol
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	604 table, but direct assignment to the \code{__dict__} attribute is not
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	605 possible (i.e., you can write \code{\var{m}.__dict__['a'] = 1}, which
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	606 defines \code{\var{m}.a} to be \code{1}, but you can't write
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	607 \code{\var{m}.__dict__ = \{\}}.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	608
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	609 Modules are written like this: \code{<module 'sys'>}.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	610
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	611 \subsubsection{Classes and Class Instances}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	612 \nodename{Classes and Instances}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	613
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	614 See Chapters 3 and 7 of the \emph{Python Reference Manual} for these.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	615
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	616 \subsubsection{Functions}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	617
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	618 Function objects are created by function definitions. The only
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	619 operation on a function object is to call it:
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	620 \code{\var{func}(\var{argument-list})}.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	621
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	622 There are really two flavors of function objects: built-in functions
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	623 and user-defined functions. Both support the same operation (to call
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	624 the function), but the implementation is different, hence the
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	625 different object types.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	626
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	627 The implementation adds two special read-only attributes:
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	628 \code{\var{f}.func_code} is a function's \dfn{code
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	629 object}\obindex{code} (see below) and \code{\var{f}.func_globals} is
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	630 the dictionary used as the function's global name space (this is the
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	631 same as \code{\var{m}.__dict__} where \var{m} is the module in which
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	632 the function \var{f} was defined).
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	633
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	634
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	635 \subsubsection{Methods}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	636 \obindex{method}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	637
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	638 Methods are functions that are called using the attribute notation.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	639 There are two flavors: built-in methods (such as \code{append()} on
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	640 lists) and class instance methods. Built-in methods are described
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	641 with the types that support them.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	642
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	643 The implementation adds two special read-only attributes to class
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	644 instance methods: \code{\var{m}.im_self} is the object whose method this
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	645 is, and \code{\var{m}.im_func} is the function implementing the method.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	646 Calling \code{\var{m}(\var{arg-1}, \var{arg-2}, {\rm \ldots},
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	647 \var{arg-n})} is completely equivalent to calling
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	648 \code{\var{m}.im_func(\var{m}.im_self, \var{arg-1}, \var{arg-2}, {\rm
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	649 \ldots}, \var{arg-n})}.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	650
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	651 See the \emph{Python Reference Manual} for more information.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	652
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	653 \subsubsection{Code Objects}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	654 \obindex{code}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	655
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	656 Code objects are used by the implementation to represent
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	657 ``pseudo-compiled'' executable Python code such as a function body.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	658 They differ from function objects because they don't contain a
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	659 reference to their global execution environment. Code objects are
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	660 returned by the built-in \code{compile()} function and can be
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	661 extracted from function objects through their \code{func_code}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	662 attribute.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	663 \bifuncindex{compile}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	664 \ttindex{func_code}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	665
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	666 A code object can be executed or evaluated by passing it (instead of a
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	667 source string) to the \code{exec} statement or the built-in
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	668 \code{eval()} function.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	669 \stindex{exec}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	670 \bifuncindex{eval}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	671
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	672 See the \emph{Python Reference Manual} for more information.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	673
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	674 \subsubsection{Type Objects}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	675 \label{bltin-type-objects}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	676
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	677 Type objects represent the various object types. An object's type is
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	678 accessed by the built-in function \code{type()}. There are no special
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	679 operations on types. The standard module \code{types} defines names
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	680 for all standard built-in types.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	681 \bifuncindex{type}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	682 \refstmodindex{types}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	683
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	684 Types are written like this: \code{<type 'int'>}.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	685
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	686 \subsubsection{The Null Object}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	687 \label{bltin-null-object}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	688
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	689 This object is returned by functions that don't explicitly return a
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	690 value. It supports no special operations. There is exactly one null
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	691 object, named \code{None} (a built-in name).
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	692
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	693 It is written as \code{None}.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	694
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	695 \subsubsection{File Objects}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	696 \label{bltin-file-objects}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	697
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	698 File objects are implemented using \C{}'s \code{stdio} package and can be
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	699 created with the built-in function \code{open()} described under
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	700 Built-in Functions below. They are also returned by some other
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	701 built-in functions and methods, e.g.\ \code{posix.popen()} and
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	702 \code{posix.fdopen()} and the \code{makefile()} method of socket
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	703 objects.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	704 \bifuncindex{open}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	705 \refbimodindex{posix}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	706 \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	707
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	708 When a file operation fails for an I/O-related reason, the exception
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	709 \code{IOError} is raised. This includes situations where the
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	710 operation is not defined for some reason, like \code{seek()} on a tty
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	711 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	712
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	713 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	714
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	715
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	716 \begin{methoddesc}[file]{close}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	717 Close the file. A closed file cannot be read or written anymore.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	718 \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	719
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	720 \begin{methoddesc}[file]{flush}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	721 Flush the internal buffer, like \code{stdio}'s \code{fflush()}.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	722 \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	723
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	724 \begin{methoddesc}[file]{isatty}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	725 Return \code{1} if the file is connected to a tty(-like) device, else
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	726 \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	727 \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	728
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	729 \begin{methoddesc}[file]{fileno}{}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	730 Return the integer ``file descriptor'' that is used by the underlying
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	731 implementation to request I/O operations from the operating system.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	732 This can be useful for other, lower level interfaces that use file
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	733 descriptors, e.g. module \code{fcntl} or \code{os.read()} and friends.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	734 \refbimodindex{fcntl}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	735 \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	736
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	737 \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	738 Read at most \var{size} bytes from the file (less if the read hits
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	739 \EOF{} or no more data is immediately available on a pipe, tty or
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	740 similar device). If the \var{size} argument is negative or omitted,
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	741 read all data until \EOF{} is reached. The bytes are returned as a string
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	742 object. An empty string is returned when \EOF{} is encountered
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	743 immediately. (For certain files, like ttys, it makes sense to
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	744 continue reading after an \EOF{} is hit.)
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	745 \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	746
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	747 \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	748 Read one entire line from the file. A trailing newline character is
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	749 kept in the string%
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	750 \footnote{The advantage of leaving the newline on is that an empty string
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	751 can be returned to mean \EOF{} without being ambiguous. Another
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	752 advantage is that (in cases where it might matter, e.g. if you
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	753 want to make an exact copy of a file while scanning its lines)
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	754 you can tell whether the last line of a file ended in a newline
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	755 or not (yes this happens!).}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	756 (but may be absent when a file ends with an
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	757 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	758 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	759 newline) and an incomplete line may be returned.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	760 An empty string is returned when \EOF{} is hit
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	761 immediately. Note: unlike \code{stdio}'s \cfunction{fgets()}, the returned
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	762 string contains null characters (\code{'\e 0'}) if they occurred in the
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	763 input.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	764 \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	765
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	766 \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	767 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	768 the lines thus read. If the optional \var{sizehint} argument is
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	769 present, instead of reading up to \EOF{}, whole lines totalling
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	770 approximately \var{sizehint} bytes (possibly after rounding up to an
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	771 internal buffer size) are read.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	772 \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	773
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	774 \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	775 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	776 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	777 (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	778 relative to the current position) and \code{2} (seek relative to the
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	779 file's end). There is no return value.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	780 \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	781
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	782 \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	783 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	784 \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	785 \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	786
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	787 \begin{methoddesc}[file]{truncate}{\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	788 Truncate the file's size. If the optional size argument present, the
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	789 file is truncated to (at most) that size. The size defaults to the
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	790 current position. Availability of this function depends on the
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	791 operating system version (e.g., not all \UNIX{} versions support this
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	792 operation).
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	793 \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	794
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	795 \begin{methoddesc}[file]{write}{str}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	796 Write a string to the file. There is no return value. Note: due to
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	797 buffering, the string may not actually show up in the file until
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	798 the \method{flush()} or \method{close()} method is called.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	799 \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	800
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	801 \begin{methoddesc}[file]{writelines}{list}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	802 Write a list of strings to the file. There is no return value.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	803 (The name is intended to match \method{readlines()};
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	804 \method{writelines()} does not add line separators.)
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	805 \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	806
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	807
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	808 File objects also offer the following attributes:
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	809
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	810 \begin{memberdesc}[file]{closed}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	811 Boolean indicating the current state of the file object. This is a
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	812 read-only attribute; the \method{close()} method changes the value.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	813 \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	814
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	815 \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	816 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	817 \function{open()} built-in function, this will be the value of the
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	818 \var{mode} parameter. This is a read-only attribute.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	819 \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	820
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	821 \begin{memberdesc}[file]{name}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	822 If the file object was created using \function{open()}, the name of
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	823 the file. Otherwise, some string that indicates the source of the
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	824 file object, of the form \samp{<\mbox{\ldots}>}. This is a read-only
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	825 attribute.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	826 \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	827
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	828 \begin{memberdesc}[file]{softspace}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	829 Boolean that indicates whether a space character needs to be printed
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	830 before another value when using the \keyword{print} statement.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	831 Classes that are trying to simulate a file object should also have a
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	832 writable \member{softspace} attribute, which should be initialized to
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	833 zero. This will be automatic for classes implemented in Python; types
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	834 implemented in \C{} will have to provide a writable \member{softspace}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	835 attribute.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	836 \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	837
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	838 \subsubsection{Internal Objects}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	839
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	840 See the \emph{Python Reference Manual} for this information. It
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	841 describes code objects, stack frame objects, traceback objects, and
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	842 slice objects.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	843
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	844
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	845 \subsection{Special Attributes}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	846 \label{specialattrs}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	847
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	848 The implementation adds a few special read-only attributes to several
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	849 object types, where they are relevant:
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	850
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	851 \begin{itemize}
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	852
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	853 \item
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	854 \code{\var{x}.__dict__} is a dictionary of some sort used to store an
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	855 object's (writable) attributes;
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	856
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	857 \item
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	858 \code{\var{x}.__methods__} lists the methods of many built-in object types,
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	859 e.g., \code{[].__methods__} yields
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	860 \code{['append', 'count', 'index', 'insert', 'pop', 'remove', 'reverse', 'sort']};
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	861
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	862 \item
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	863 \code{\var{x}.__members__} lists data attributes;
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	864
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	865 \item
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	866 \code{\var{x}.__class__} is the class to which a class instance belongs;
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	867
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	868 \item
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	869 \code{\var{x}.__bases__} is the tuple of base classes of a class object.
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	870
8a306dfd9f33 Move files around to get the names to match the module names except for Fred Drake <fdrake@acm.org> parents: diff changeset	871 \end{itemize}

Mercurial > cpython-lru_cache-weakref

annotate Doc/lib/libstdtypes.tex @ 8730:8a306dfd9f33 legacy-trunk