Doc/liboperator.tex

   1 % Contributed by Skip Montanaro, from the module's doc strings.
   2
   3 \section{Built-in Module \module{operator}}
   4 \label{module-operator}
   5 \bimodindex{operator}
   6
   7 The \module{operator} module exports a set of functions implemented in C
   8 corresponding to the intrinsic operators of Python.  For example,
   9 \code{operator.add(x, y)} is equivalent to the expression \code{x+y}.  The
  10 function names are those used for special class methods; variants without
  11 leading and trailing \samp{__} are also provided for convenience.
  12
  13 The \module{operator} module defines the following functions:
  14
  15 \begin{funcdesc}{add}{a, b}
  16 \funcline{__add__}{a, b}
  17 Return \var{a} \code{+} \var{b}, for \var{a} and \var{b} numbers.
  18 \end{funcdesc}
  19
  20 \begin{funcdesc}{sub}{a, b}
  21 \funcline{__sub__}{a, b}
  22 Return \var{a} \code{-} \var{b}.
  23 \end{funcdesc}
  24
  25 \begin{funcdesc}{mul}{a, b}
  26 \funcline{__mul__}{a, b}
  27 Return \var{a} \code{*} \var{b}, for \var{a} and \var{b} numbers.
  28 \end{funcdesc}
  29
  30 \begin{funcdesc}{div}{a, b}
  31 \funcline{__div__}{a, b}
  32 Return \var{a} \code{/} \var{b}.
  33 \end{funcdesc}
  34
  35 \begin{funcdesc}{mod}{a, b}
  36 \funcline{__mod__}{a, b}
  37 Return \var{a} \code{\%} \var{b}.
  38 \end{funcdesc}
  39
  40 \begin{funcdesc}{neg}{o}
  41 \funcline{__neg__}{o}
  42 Return \var{o} negated.
  43 \end{funcdesc}
  44
  45 \begin{funcdesc}{pos}{o}
  46 \funcline{__pos__}{o}
  47 Return \var{o} positive.
  48 \end{funcdesc}
  49
  50 \begin{funcdesc}{abs}{o}
  51 \funcline{__abs__}{o}
  52 Return the absolute value of \var{o}.
  53 \end{funcdesc}
  54
  55 \begin{funcdesc}{inv}{o}
  56 \funcline{__inv__}{o}
  57 Return the inverse of \var{o}.
  58 \end{funcdesc}
  59
  60 \begin{funcdesc}{lshift}{a, b}
  61 \funcline{__lshift__}{a, b}
  62 Return \var{a} shifted left by \var{b}.
  63 \end{funcdesc}
  64
  65 \begin{funcdesc}{rshift}{a, b}
  66 \funcline{__rshift__}{a, b}
  67 Return \var{a} shifted right by \var{b}.
  68 \end{funcdesc}
  69
  70 \begin{funcdesc}{and_}{a, b}
  71 \funcline{__and__}{a, b}
  72 Return the bitwise and of \var{a} and \var{b}.
  73 \end{funcdesc}
  74
  75 \begin{funcdesc}{or_}{a, b}
  76 \funcline{__or__}{a, b}
  77 Return the bitwise or of \var{a} and \var{b}.
  78 \end{funcdesc}
  79
  80 \begin{funcdesc}{concat}{a, b}
  81 \funcline{__concat__}{a, b}
  82 Return \var{a} \code{+} \var{b} for \var{a} and \var{b} sequences.
  83 \end{funcdesc}
  84
  85 \begin{funcdesc}{repeat}{a, b}
  86 \funcline{__repeat__}{a, b}
  87 Return \var{a} \code{*} \var{b} where \var{a} is a sequence and
  88 \var{b} is an integer.
  89 \end{funcdesc}
  90
  91 \begin{funcdesc}{getitem}{a, b}
  92 \funcline{__getitem__}{a, b}
  93 Return the value of \var{a} at index \var{b}.
  94 \end{funcdesc}
  95
  96 \begin{funcdesc}{setitem}{a, b, c}
  97 \funcline{__setitem__}{a, b, c}
  98 Set the value of \var{a} at index \var{b} to \var{c}.
  99 \end{funcdesc}
 100
 101 \begin{funcdesc}{delitem}{a, b}
 102 \funcline{__delitem__}{a, b}
 103 Remove the value of \var{a} at index \var{b}.
 104 \end{funcdesc}
 105
 106 \begin{funcdesc}{getslice}{a, b, c}
 107 \funcline{__getslice__}{a, b, c}
 108 Return the slice of \var{a} from index \var{b} to index \var{c}\code{-1}.
 109 \end{funcdesc}
 110
 111 \begin{funcdesc}{setslice}{a, b, c, v}
 112 \funcline{__setslice__}{a, b, c, v}
 113 Set the slice of \var{a} from index \var{b} to index \var{c}\code{-1} to the
 114 sequence \var{v}.
 115 \end{funcdesc}
 116
 117 \begin{funcdesc}{delslice}{a, b, c}
 118 \funcline{__delslice__}{a, b, c}
 119 Delete the slice of \var{a} from index \var{b} to index \var{c}\code{-1}.
 120 \end{funcdesc}
 121
 122
 123 Example: Build a dictionary that maps the ordinals from \code{0} to
 124 \code{256} to their character equivalents.
 125
 126 \begin{verbatim}
 127 >>> import operator
 128 >>> d = {}
 129 >>> keys = range(256)
 130 >>> vals = map(chr, keys)
 131 >>> map(operator.setitem, [d]*len(keys), keys, vals)
 132 \end{verbatim}