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| -rw-r--r-- | Doc/lib/liboperator.tex | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/Doc/lib/liboperator.tex b/Doc/lib/liboperator.tex index 9cf25a0..69ae23b 100644 --- a/Doc/lib/liboperator.tex +++ b/Doc/lib/liboperator.tex @@ -159,6 +159,56 @@ sequence \var{v}. Delete the slice of \var{a} from index \var{b} to index \var{c}\code{-1}. \end{funcdesc} +The \module{operator} also defines a few predicates to test the type +of objects. \strong{Note:} Be careful not to misinterpret the +results of these functions; only \function{isCallable()} has any +measure of reliability with instance objects. For example: + +\begin{verbatim} +>>> class C: +... pass +... +>>> import operator +>>> o = C() +>>> operator.isMappingType(o) +1 +\end{verbatim} + +\begin{funcdesc}{isCallable}{o} +\deprecated{2.0}{Use the \function{callable()} built-in function instead.} +Returns true if the object \var{o} can be called like a function, +otherwise it returns false. True is returned for functions, bound and +unbound methods, class objects, and instance objects which support the +\method{__call__()} method. +\end{funcdesc} + +\begin{funcdesc}{isMappingType}{o} +Returns true if the object \var{o} supports the mapping interface. +This is true for dictionaries and all instance objects. +\strong{Warning:} There is no reliable way to test if an instance +supports the complete mapping protocol since the interface itself is +ill-defined. This makes this test less useful than it otherwise might +be. +\end{funcdesc} + +\begin{funcdesc}{isNumberType}{o} +Returns true if the object \var{o} represents a number. This is true +for all numeric types implemented in C, and for all instance objects. +\strong{Warning:} There is no reliable way to test if an instance +supports the complete numeric interface since the interface itself is +ill-defined. This makes this test less useful than it otherwise might +be. +\end{funcdesc} + +\begin{funcdesc}{isSequenceType}{o} +Returns true if the object \var{o} supports the sequence protocol. +This returns true for all objects which define sequence methods in C, +and for all instance objects. \strong{Warning:} There is no reliable +way to test if an instance supports the complete sequence interface +since the interface itself is ill-defined. This makes this test less +useful than it otherwise might be. +\end{funcdesc} + Example: Build a dictionary that maps the ordinals from \code{0} to \code{256} to their character equivalents. |