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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 e568ddf..b61ec08 100644 --- a/Doc/reference/expressions.rst +++ b/Doc/reference/expressions.rst @@ -1031,9 +1031,9 @@ 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}`` @@ -1330,15 +1330,6 @@ 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 |