diff options
Diffstat (limited to 'Doc/howto/sorting.rst')
| -rw-r--r-- | Doc/howto/sorting.rst | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/Doc/howto/sorting.rst b/Doc/howto/sorting.rst index 351713f2cf..d9c70e2d8a 100644 --- a/Doc/howto/sorting.rst +++ b/Doc/howto/sorting.rst @@ -23,7 +23,7 @@ returns a new sorted list:: >>> sorted([5, 2, 3, 1, 4]) [1, 2, 3, 4, 5] -You can also use the :meth:`list.sort` method of a list. It modifies the list +You can also use the :meth:`list.sort` method. It modifies the list in-place (and returns *None* to avoid confusion). Usually it's less convenient than :func:`sorted` - but if you don't need the original list, it's slightly more efficient. @@ -87,9 +87,9 @@ Operator Module Functions ========================= The key-function patterns shown above are very common, so Python provides -convenience functions to make accessor functions easier and faster. The operator -module has :func:`operator.itemgetter`, :func:`operator.attrgetter`, and -an :func:`operator.methodcaller` function. +convenience functions to make accessor functions easier and faster. The +:mod:`operator` module has :func:`~operator.itemgetter`, +:func:`~operator.attrgetter`, and an :func:`~operator.methodcaller` function. Using those functions, the above examples become simpler and faster: @@ -247,6 +247,8 @@ To convert to a key function, just wrap the old comparison function: >>> sorted([5, 2, 4, 1, 3], key=cmp_to_key(reverse_numeric)) [5, 4, 3, 2, 1] +In Python 3.2, the :func:`functools.cmp_to_key` function was added to the +:mod:`functools` module in the standard library. Odd and Ends ============ @@ -254,7 +256,7 @@ Odd and Ends * For locale aware sorting, use :func:`locale.strxfrm` for a key function or :func:`locale.strcoll` for a comparison function. -* The *reverse* parameter still maintains sort stability (i.e. records with +* The *reverse* parameter still maintains sort stability (so that records with equal keys retain the original order). Interestingly, that effect can be simulated without the parameter by using the builtin :func:`reversed` function twice: |