PERF: optimize Index.delete for dtype=object

doc/source/release.rst

@@ -124,8 +124,9 @@ API Changes
 
 - ``concat`` will now concatenate mixed Series and DataFrames using the Series name
   or numbering columns as needed (:issue:`2385`)
-- Slicing and advanced/boolean indexing operations on ``Index`` classes will no
-  longer change type of the resulting index (:issue:`6440`).
+- Slicing and advanced/boolean indexing operations on ``Index`` classes as well
+  as :meth:`Index.delete` and :meth:`Index.drop` methods will no longer change type of the
+  resulting index (:issue:`6440`, :issue:`7040`)
 - ``set_index`` no longer converts MultiIndexes to an Index of tuples (:issue:`6459`).
 - Slicing with negative start, stop & step values handles corner cases better (:issue:`6531`):
 

doc/source/v0.14.0.txt

@@ -163,13 +163,15 @@ API changes
 
 - ``concat`` will now concatenate mixed Series and DataFrames using the Series name
   or numbering columns as needed (:issue:`2385`). See :ref:`the docs <merging.mixed_ndims>`
-- Slicing and advanced/boolean indexing operations on ``Index`` classes will no
-  longer change type of the resulting index (:issue:`6440`)
+- Slicing and advanced/boolean indexing operations on ``Index`` classes as well
+  as :meth:`Index.delete` and :meth:`Index.drop` methods will no longer change type of the
+  resulting index (:issue:`6440`, :issue:`7040`)
 
   .. ipython:: python
 
      i = pd.Index([1, 2, 3, 'a' , 'b', 'c'])
      i[[0,1,2]]
+     i.drop(['a', 'b', 'c'])
 
   Previously, the above operation would return ``Int64Index``.  If you'd like
   to do this manually, use :meth:`Index.astype`

pandas/core/index.py

@@ -1760,14 +1760,13 @@ def slice_locs(self, start=None, end=None):
 
     def delete(self, loc):
         """
-        Make new Index with passed location deleted
+        Make new Index with passed location(-s) deleted
 
         Returns
         -------
         new_index : Index
         """
-        arr = np.delete(self.values, loc)
-        return Index(arr)
+        return np.delete(self, loc)
 
     def insert(self, loc, item):
         """