commit e9cbcd0018abd2a5f2348c45d5c9c4265c4f42dc
author sweeneyde <36520290+sweeneyde@users.noreply.github.com> Wed Aug 07 00:37:08 2019 -0400
committer Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com> Tue Aug 06 21:37:08 2019 -0700
tree 0eebe37ba186d8615ee291b49a304bbd58cafa12
parent 610a4823cc0a3c2380ad0dfe64ae483ced4e5304

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



https://bugs.python.org/issue37004

Doc/library/difflib.rst

diff --git a/Doc/library/difflib.rst b/Doc/library/difflib.rst
index f044cb2..e245ab8 100644
--- a/Doc/library/difflib.rst
+++ b/Doc/library/difflib.rst
@@ -543,6 +543,16 @@
       to try :meth:`quick_ratio` or :meth:`real_quick_ratio` first to get an
       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()