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| author | Senthil Kumaran <orsenthil@gmail.com> | 2010-07-14 20:32:56 (GMT) |
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| committer | Senthil Kumaran <orsenthil@gmail.com> | 2010-07-14 20:32:56 (GMT) |
| commit | 09cfa890d2258e4b969fd338293a068f48e899d4 (patch) | |
| tree | 8a371c082ae194c8750628c06206889d883e2f6b /Doc/reference | |
| parent | 1ea57a6c5f3a78dd28349dbb58639385cc53788a (diff) | |
| download | cpython-09cfa890d2258e4b969fd338293a068f48e899d4.zip cpython-09cfa890d2258e4b969fd338293a068f48e899d4.tar.gz cpython-09cfa890d2258e4b969fd338293a068f48e899d4.tar.bz2 | |
Merged revisions 82899 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k
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r82899 | senthil.kumaran | 2010-07-15 02:00:02 +0530 (Thu, 15 Jul 2010) | 2 lines
Fix issue9132 - Documentation for comparing dictionaries is out of date
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Diffstat (limited to 'Doc/reference')
| -rw-r--r-- | Doc/reference/expressions.rst | 15 |
1 files changed, 3 insertions, 12 deletions
diff --git a/Doc/reference/expressions.rst b/Doc/reference/expressions.rst index f0bf841..dff9cc3 100644 --- a/Doc/reference/expressions.rst +++ b/Doc/reference/expressions.rst @@ -1026,9 +1026,9 @@ Comparison of objects of the same type depends on the type: ``x <= y``. If the corresponding element does not exist, the shorter sequence is ordered first (for example, ``[1,2] < [1,2,3]``). -* Mappings (dictionaries) compare equal if and only if their sorted ``(key, - value)`` lists compare equal. [#]_ Outcomes other than equality are resolved - consistently, but are not otherwise defined. [#]_ +* Mappings (dictionaries) compare equal if and only if they have the same + ``(key, value)`` pairs. Order comparisons ``('<', '<=', '>=', '>')`` + raise :exc:`TypeError`. * Sets and frozensets define comparison operators to mean subset and superset tests. Those relations do not define total orderings (the two sets ``{1,2}`` @@ -1310,15 +1310,6 @@ groups from right to left). strings in a human recognizable way, compare using :func:`unicodedata.normalize`. -.. [#] The implementation computes this efficiently, without constructing lists - or sorting. - -.. [#] Earlier versions of Python used lexicographic comparison of the sorted (key, - value) lists, but this was very expensive for the common case of comparing - for equality. An even earlier version of Python compared dictionaries by - identity only, but this caused surprises because people expected to be able - to test a dictionary for emptiness by comparing it to ``{}``. - .. [#] Due to automatic garbage-collection, free lists, and the dynamic nature of descriptors, you may notice seemingly unusual behaviour in certain uses of the :keyword:`is` operator, like those involving comparisons between instance |