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| -rw-r--r-- | Doc/whatsnew/whatsnew24.tex | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/Doc/whatsnew/whatsnew24.tex b/Doc/whatsnew/whatsnew24.tex index 05b06b5..e0e2c9c 100644 --- a/Doc/whatsnew/whatsnew24.tex +++ b/Doc/whatsnew/whatsnew24.tex @@ -294,6 +294,21 @@ return consecutive runs of odd or even numbers. >>> \end{verbatim} +Like its SQL counterpart, \function{groupby()} is typically used with +sorted input. The logic for \function{groupby()} is similar to the +\UNIX{} \code{uniq} filter which makes it handy for eliminating, +counting, or identifying duplicate elements: + +\begin{verbatim} +>>> word = 'abracadabra' +>>> [k for k, g in groupby(list.sorted(word))] +['a', 'b', 'c', 'd', 'r'] +>>> [(k, len(list(g))) for k, g in groupby(list.sorted(word))] +[('a', 5), ('b', 2), ('c', 1), ('d', 1), ('r', 2)] +>>> [k for k, g in groupby(list.sorted(word)) if len(list(g)) > 1] +['a', 'b', 'r'] +\end{verbatim} + \item A new \function{getsid()} function was added to the \module{posix} module that underlies the \module{os} module. (Contributed by J. Raynor.) |