diff --git a/Doc/lib/libfuncs.tex b/Doc/lib/libfuncs.tex index 860321d637e..6b7a68821a0 100644 --- a/Doc/lib/libfuncs.tex +++ b/Doc/lib/libfuncs.tex @@ -1008,8 +1008,30 @@ except NameError: \begin{funcdesc}{sorted}{iterable\optional{, cmp\optional{, key\optional{, reverse}}}} Return a new sorted list from the items in \var{iterable}. - The optional arguments \var{cmp}, \var{key}, and \var{reverse} - have the same meaning as those for the \method{list.sort()} method. + + The optional arguments \var{cmp}, \var{key}, and \var{reverse} have + the same meaning as those for the \method{list.sort()} method + (described in section~\ref{typesseq-mutable}). + + \var{cmp} specifies a custom comparison function of two arguments + (iterable elements) which should return a negative, zero or positive + number depending on whether the first argument is considered smaller + than, equal to, or larger than the second argument: + \samp{\var{cmp}=\keyword{lambda} \var{x},\var{y}: + \function{cmp}(x.lower(), y.lower())} + + \var{key} specifies a function of one argument that is used to + extract a comparison key from each list element: + \samp{\var{key}=\function{str.lower}} + + \var{reverse} is a boolean value. If set to \code{True}, then the + list elements are sorted as if each comparison were reversed. + + In general, the \var{key} and \var{reverse} conversion processes are + much faster than specifying an equivalent \var{cmp} function. This is + because \var{cmp} is called multiple times for each list element while + \var{key} and \var{reverse} touch each element only once. + \versionadded{2.4} \end{funcdesc}