fix

Author: Moons08

pandas/core/indexes/base.py

@@ -1284,40 +1284,43 @@ def set_names(self, names, level=None, inplace=False):
 
         Parameters
         ----------
-        names : int, str, list-like, optional
+        names : label or list of labels
             Name(s) to set.
-        level : int, str, list-like, optional, default None
-            If the index is a MultiIndex(hierarchical), level(s) to set (None
-            for all levels). Otherwise level must be None.
+        level : int, str or list of labels, optional
+            If the index is a MultiIndex, level(s) to set (None for all
+            levels). Otherwise level must be None.
         inplace : boolean, default False
             Modifies the object directly, instead of creating a new Index or
             MultiIndex.
 
         Returns
         -------
-        renamed : Index, MultiIndex or None
+        Index
             The same type as the caller or None if inplace is True.
 
-        See also
+        See Also
         --------
-        Index.rename : Able to set new names without level
+        Index.rename : Able to set new names without level.
 
         Examples
         --------
-        >>> pd.Index([1, 2, 3, 4]).set_names('foo')
-        Int64Index([1, 2, 3, 4], dtype='int64', name='foo')
+        >>> idx = pd.Index([1, 2, 3, 4])
+        >>> idx
+        Int64Index([1, 2, 3, 4], dtype='int64')
+        >>> idx.set_names('quarter')
+        Int64Index([1, 2, 3, 4], dtype='int64', name='quarter')
 
         >>> idx = pd.MultiIndex.from_tuples([(1, 'one'), (1, 'two'),
         ...                                  (2, 'one'), (2, 'two')],
-        ...                                  names=['foo', 'bar'])
-        >>> idx.set_names(['baz', 'quz'])
+        ...                                  names=['year', 'company'])
+        >>> idx.set_names(['term', 'corporation'])
         MultiIndex(levels=[[1, 2], ['one', 'two']],
                    labels=[[0, 0, 1, 1], [0, 1, 0, 1]],
-                   names=['baz', 'quz'])
-        >>> idx.set_names('baz', level=0)
+                   names=['term', 'corporation'])
+        >>> idx.set_names('association', level=1)
         MultiIndex(levels=[[1, 2], ['one', 'two']],
                    labels=[[0, 0, 1, 1], [0, 1, 0, 1]],
-                   names=['baz', 'bar'])
+                   names=['year', 'association'])
         """
 
         from .multi import MultiIndex
@@ -1326,7 +1329,7 @@ def set_names(self, names, level=None, inplace=False):
 
         if level is not None and not is_list_like(level) and is_list_like(
                 names):
-            msg = "Length of names must match number of levels in MultiIndex."
+            msg = "Names must be a string when one level is provided."
             raise TypeError(msg)
 
         if not is_list_like(names) and level is None and self.nlevels > 1:
@@ -1354,37 +1357,37 @@ def rename(self, name, inplace=False):
 
         Parameters
         ----------
-        name : int, str, list-like, optional
+        name : label or list of labels
             Name(s) to set.
         inplace : boolean, default False
             Modifies the object directly, instead of creating a new Index or
             MultiIndex.
 
         Returns
         -------
-        renamed : Index, MultiIndex or None
+        Index
             The same type as the caller or None if inplace is True.
 
-        See also
+        See Also
         --------
-        Index.set_names : Able to set new names partially and by level
+        Index.set_names : Able to set new names partially and by level.
 
         Examples
         --------
-        >>> idx = pd.Index([1, 2, 3, 4], name='foo')
-        >>> idx.rename('bar')
-        Int64Index([1, 2, 3, 4], dtype='int64', name='bar')
+        >>> idx = pd.Index(['A', 'C', 'A', 'B'], name='score')
+        >>> idx.rename('grade')
+        Index(['A', 'C', 'A', 'B'], dtype='object', name='grade')
 
         >>> idx = pd.MultiIndex.from_tuples([(1, 'one'), (1, 'two'),
         ...                                  (2, 'one'), (2, 'two')],
-        ...                                  names=['foo', 'bar'])
-        >>> idx.rename(['bar', None])
+        ...                                  names=['year', 'company'])
+        >>> idx.rename(['term', 'corporation'])
         MultiIndex(levels=[[1, 2], ['one', 'two']],
                    labels=[[0, 0, 1, 1], [0, 1, 0, 1]],
-                   names=['bar', None])
-        >>> idx.rename(['bar'])
+                   names=['term', 'corporation'])
+        >>> idx.rename('term')
         Traceback (most recent call last):
-        ValueError: Length of names must match number of levels in MultiIndex.
+        TypeError: Must pass list-like as `names`.
         """
         return self.set_names([name], inplace=inplace)
 

pandas/tests/indexes/multi/test_get_set.py

@@ -360,7 +360,7 @@ def test_set_levels_labels_names_bad_input(idx):
     with tm.assert_raises_regex(ValueError, 'Length of names'):
         idx.set_names(names[0], level=[0, 1])
 
-    with tm.assert_raises_regex(TypeError, 'Length of names'):
+    with tm.assert_raises_regex(TypeError, 'Names must be a'):
         idx.set_names(names, level=0)