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| -rw-r--r-- | Doc/library/functools.rst | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/Doc/library/functools.rst b/Doc/library/functools.rst index 7fd7d58..d87fa58 100644 --- a/Doc/library/functools.rst +++ b/Doc/library/functools.rst @@ -21,8 +21,8 @@ The :mod:`functools` module defines the following functions: .. function:: cmp_to_key(func) - Transform an old-style comparison function to a key function. Used with - tools that accept key functions (such as :func:`sorted`, :func:`min`, + Transform an old-style comparison function to a :term:`key function`. Used + with tools that accept key functions (such as :func:`sorted`, :func:`min`, :func:`max`, :func:`heapq.nlargest`, :func:`heapq.nsmallest`, :func:`itertools.groupby`). This function is primarily used as a transition tool for programs being converted from Python 2 which supported the use of @@ -31,13 +31,14 @@ The :mod:`functools` module defines the following functions: A comparison function is any callable that accept two arguments, compares them, and returns a negative number for less-than, zero for equality, or a positive number for greater-than. A key function is a callable that accepts one - argument and returns another value indicating the position in the desired - collation sequence. + argument and returns another value to be used as the sort key. Example:: sorted(iterable, key=cmp_to_key(locale.strcoll)) # locale-aware sort order + For sorting examples and a brief sorting tutorial, see :ref:`sortinghowto`. + .. versionadded:: 3.2 |