DOC: Fix renaming categories section (#21264)

JarnoRFB · jorisvandenbossche · commit e1b6cbffd8fd · 2018-05-31T10:29:22.000+02:00
The categories were not correctly saved so that the renaming using the
dict-like object had no effect.
diff --git a/doc/source/categorical.rst b/doc/source/categorical.rst
@@ -358,10 +358,10 @@ Renaming categories is done by assigning new values to the
     s
     s.cat.categories = ["Group %s" % g for g in s.cat.categories]
     s
-    s.cat.rename_categories([1,2,3])
+    s = s.cat.rename_categories([1,2,3])
     s
     # You can also pass a dict-like object to map the renaming
-    s.cat.rename_categories({1: 'x', 2: 'y', 3: 'z'})
+    s = s.cat.rename_categories({1: 'x', 2: 'y', 3: 'z'})
     s
 
 .. note::

Original file line number	Diff line number	Diff line change
`@@ -358,10 +358,10 @@ Renaming categories is done by assigning new values to the`
`358`	`358`	`s`
`359`	`359`	`s.cat.categories = ["Group %s" % g for g in s.cat.categories]`
`360`	`360`	`s`
`361`		`- s.cat.rename_categories([1,2,3])`
	`361`	`+ s = s.cat.rename_categories([1,2,3])`
`362`	`362`	`s`
`363`	`363`	`# You can also pass a dict-like object to map the renaming`
`364`		`- s.cat.rename_categories({1: 'x', 2: 'y', 3: 'z'})`
	`364`	`+ s = s.cat.rename_categories({1: 'x', 2: 'y', 3: 'z'})`
`365`	`365`	`s`
`366`	`366`
`367`	`367`	`.. note::`