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| author | Raymond Hettinger <python@rcn.com> | 2008-02-09 03:48:16 (GMT) |
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| committer | Raymond Hettinger <python@rcn.com> | 2008-02-09 03:48:16 (GMT) |
| commit | 0dbdab2557d7e1f83929981a12d7d2619a2a3804 (patch) | |
| tree | 8520e32284d37f1b86e40f0ab58a46dcba53bb2e /Doc/library/collections.rst | |
| parent | 7aebb64bab2ef75c6d9ae55da9ae7049f05c8670 (diff) | |
| download | cpython-0dbdab2557d7e1f83929981a12d7d2619a2a3804.zip cpython-0dbdab2557d7e1f83929981a12d7d2619a2a3804.tar.gz cpython-0dbdab2557d7e1f83929981a12d7d2619a2a3804.tar.bz2 | |
Add another usage note for collections.Set
Diffstat (limited to 'Doc/library/collections.rst')
| -rw-r--r-- | Doc/library/collections.rst | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/Doc/library/collections.rst b/Doc/library/collections.rst index 1e32f99..493e22a 100644 --- a/Doc/library/collections.rst +++ b/Doc/library/collections.rst @@ -58,7 +58,7 @@ ABC Inherits Abstract Methods Mixin M ``insert``, ``remove``, and ``__iadd__`` and ``__len__`` -:class:`Set` \(1) \(2) :class:`Sized`, ``__len__``, ``__le__``, ``__lt__``, ``__eq__``, ``__ne__``, +:class:`Set` :class:`Sized`, ``__len__``, ``__le__``, ``__lt__``, ``__eq__``, ``__ne__``, :class:`Iterable`, ``__iter__``, and ``__gt__``, ``__ge__``, ``__and__``, ``__or__`` :class:`Container` ``__contains__`` ``__sub__``, ``__xor__``, and ``isdisjoint`` @@ -118,6 +118,13 @@ Notes on using :class:`Set` and :class:`MutableSet` as a mixin: semantics are fixed), redefine :meth:`__le__` and then the other operations will automatically follow suit. +(3) + The :class:`Set` mixin provides a :meth:`_hash` method to compute a hash value + for the set; however, :meth:`__hash__` is not defined because not all sets + are hashable or immutable. To add set hashabilty using mixins, + inherit from both :meth:`Set` and :meth:`Hashable`, then define + ``__hash__ = Set._hash``. + (For more about ABCs, see the :mod:`abc` module and :pep:`3119`.) |