bpo-37004: Documented asymmetry of string arguments in difflib.SequenceMatcher for ratio method (GH-13482)

https://bugs.python.org/issue37004
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sweeneyde 2019-08-07 00:37:08 -04:00 committed by Miss Islington (bot)
parent 610a4823cc
commit e9cbcd0018
2 changed files with 11 additions and 0 deletions

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@ -543,6 +543,16 @@ The :class:`SequenceMatcher` class has this constructor:
to try :meth:`quick_ratio` or :meth:`real_quick_ratio` first to get an to try :meth:`quick_ratio` or :meth:`real_quick_ratio` first to get an
upper bound. upper bound.
.. note::
Caution: The result of a :meth:`ratio` call may depend on the order of
the arguments. For instance::
>>> SequenceMatcher(None, 'tide', 'diet').ratio()
0.25
>>> SequenceMatcher(None, 'diet', 'tide').ratio()
0.5
.. method:: quick_ratio() .. method:: quick_ratio()

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@ -0,0 +1 @@
In the documentation for difflib, a note was added explicitly warning that the results of SequenceMatcher's ratio method may depend on the order of the input strings.