DOC: update the MultiIndex.swaplevel docstring (pandas-dev#20105)

Author: xrmx

pandas/core/indexes/multi.py

@@ -1775,22 +1775,45 @@ def droplevel(self, level=0):
 
     def swaplevel(self, i=-2, j=-1):
         """
-        Swap level i with level j. Do not change the ordering of anything
+        Swap level i with level j.
+
+        Calling this method does not change the ordering of the values.
 
         Parameters
         ----------
-        i, j : int, string (can be mixed)
-            Level of index to be swapped. Can pass level name as string.
+        i : int, str, default -2
+            First level of index to be swapped. Can pass level name as string.
+            Type of parameters can be mixed.
+        j : int, str, default -1
+            Second level of index to be swapped. Can pass level name as string.
+            Type of parameters can be mixed.
 
         Returns
         -------
-        swapped : MultiIndex
+        MultiIndex
+            A new MultiIndex
 
         .. versionchanged:: 0.18.1
 
            The indexes ``i`` and ``j`` are now optional, and default to
            the two innermost levels of the index.
 
+        See Also
+        --------
+        Series.swaplevel : Swap levels i and j in a MultiIndex
+        Dataframe.swaplevel : Swap levels i and j in a MultiIndex on a
+            particular axis
+
+        Examples
+        --------
+        >>> mi = pd.MultiIndex(levels=[['a', 'b'], ['bb', 'aa']],
+        ...                    labels=[[0, 0, 1, 1], [0, 1, 0, 1]])
+        >>> mi
+        MultiIndex(levels=[['a', 'b'], ['bb', 'aa']],
+           labels=[[0, 0, 1, 1], [0, 1, 0, 1]])
+        >>> mi.swaplevel(0, 1)
+        MultiIndex(levels=[['bb', 'aa'], ['a', 'b']],
+           labels=[[0, 1, 0, 1], [0, 0, 1, 1]])
         """
         new_levels = list(self.levels)
         new_labels = list(self.labels)