Address requested changes

Author: Albert Villanova del Moral

doc/source/whatsnew/v0.20.0.txt

@@ -308,7 +308,7 @@ Other enhancements
 - ``pd.types.concat.union_categoricals`` gained the ``ignore_ordered`` argument to allow ignoring the ordered attribute of unioned categoricals (:issue:`13410`). See the :ref:`categorical union docs <categorical.union>` for more information.
 - ``pandas.io.json.json_normalize()`` with an empty ``list`` will return an empty ``DataFrame`` (:issue:`15534`)
 - ``pd.DataFrame.to_latex`` and ``pd.DataFrame.to_string`` now allow optional header aliases. (:issue:`15536`)
-- ``Index.intersection()`` accepts parameter ``sort`` (:issue:`15582`)
+- ``Index.join()`` accepts parameter ``sort`` (:issue:`15582`)
 
 
 .. _ISO 8601 duration: https://en.wikipedia.org/wiki/ISO_8601#Durations
@@ -742,7 +742,6 @@ joins (methods ``Index.join``, ``DataFrame.join``, ``DataFrame.merge`` and
   .. ipython:: python
 
      idx1.intersection(idx2)
-
      idx1.join(idx2, how='inner')
 
 - ``Series.align``
@@ -830,11 +829,7 @@ joins (methods ``Index.join``, ``DataFrame.join``, ``DataFrame.merge`` and
   .. ipython:: python
 
      df1.join(df2, how='inner')
-
      df1.merge(df2, how='inner', left_index=True, right_index=True)
-
-     pd.merge(df1, df2, how='inner', left_index=True, right_index=True)
-
      (res1, res2) = df1.align(df2, axis=0, join='inner')
      res1
      res2

pandas/core/frame.py

@@ -128,7 +128,7 @@
     * right: use only keys from right frame (SQL: right outer join)
     * outer: use union of keys from both frames (SQL: full outer join)
     * inner: use intersection of keys from both frames (SQL: inner join),
-        preserving the order of the left keys
+      preserving the order of the left keys
 on : label or list
     Field names to join on. Must be found in both DataFrames. If on is
     None and not merging on indexes, then it merges on the intersection of
@@ -4515,11 +4515,11 @@ def join(self, other, on=None, how='left', lsuffix='', rsuffix='',
             * left: use calling frame's index (or column if on is specified)
             * right: use other frame's index
             * outer: form union of calling frame's index (or column if on is
-                specified) with other frame's index, and sort it
-                lexicographically
+              specified) with other frame's index, and sort it
+              lexicographically
             * inner: form intersection of calling frame's index (or column if
-                on is specified) with other frame's index, preserving the
-                order of the calling's one
+              on is specified) with other frame's index, preserving the order
+              of the calling's one
         lsuffix : string
             Suffix to use from left frame's overlapping columns
         rsuffix : string