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Document the built-in iter() function.

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Fred Drake 2001-09-06 19:04:29 +00:00
parent 7feae2d28c
commit 00bb329521
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Doc/lib/libfuncs.tex
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@ -390,6 +390,23 @@ argument is not a class object, a \exception{TypeError} exception is
raised.
\end{funcdesc}
\begin{funcdesc}{iter}{o\optional{, sentinel}}
Return an iterator object. The first argument is interpreted very
differently depending on the presence of the second argument.
Without a second argument, \var{o} must be a collection object which
supports the iteration protocol (the \method{__iter__()} method), or
it must support the sequence protocol (the \method{__getitem__()}
method with integer arguments starting at \code{0}). If it does not
support either of those protocols, \exception{TypeError} is raised.
If the second argument, \var{sentinel}, is given, then \var{o} must
be a callable object. The iterator created in this case will call
\var{o} with no arguments for each call to its \method{next()}
method; if the value returned is equal to \var{sentinel},
\exception{StopIteration} will be raised, otherwise the value will
be returned.
\versionadded{2.2}
\end{funcdesc}
\begin{funcdesc}{len}{s}
Return the length (the number of items) of an object. The argument
may be a sequence (string, tuple or list) or a mapping (dictionary).