Seth p drop duplicates names

.gitignore

@@ -41,6 +41,7 @@ doc/_build
 dist
 # Egg metadata
 *.egg-info
+.eggs
 # tox testing tool
 .tox
 # rope

doc/source/whatsnew/v0.17.0.txt

@@ -65,6 +65,6 @@ Bug Fixes
 
 - Bug in ``Timestamp``'s' ``microsecond``, ``quarter``, ``dayofyear``, ``week`` and ``daysinmonth`` properties return ``np.int`` type, not built-in ``int``. (:issue:`10050`)
 - Bug in ``NaT`` raises ``AttributeError`` when accessing to ``daysinmonth``, ``dayofweek`` properties. (:issue:`10096`)
-
+- Bug in ``drop_duplicates`` dropping name(s) (:issue:`10115`)
 
 

pandas/core/index.py

@@ -2579,14 +2579,12 @@ def drop(self, labels, errors='raise'):
 
     @Appender(_shared_docs['drop_duplicates'] % _index_doc_kwargs)
     def drop_duplicates(self, take_last=False):
-        result = super(Index, self).drop_duplicates(take_last=take_last)
-        return self._constructor(result)
+        return super(Index, self).drop_duplicates(take_last=take_last)
 
     @Appender(_shared_docs['duplicated'] % _index_doc_kwargs)
     def duplicated(self, take_last=False):
         return super(Index, self).duplicated(take_last=take_last)
 
-
     def _evaluate_with_timedelta_like(self, other, op, opstr):
         raise TypeError("can only perform ops with timedelta like values")
 

pandas/tests/test_index.py

@@ -199,10 +199,19 @@ def test_duplicates(self):
 
             if not len(ind):
                 continue
+            if isinstance(ind, MultiIndex):
+                continue
             idx = self._holder([ind[0]]*5)
             self.assertFalse(idx.is_unique)
             self.assertTrue(idx.has_duplicates)
 
+            # GH 10115
+            # preserve names
+            idx.name = 'foo'
+            result = idx.drop_duplicates()
+            self.assertEqual(result.name, 'foo')
+            self.assert_index_equal(result, Index([ind[0]],name='foo'))
+
     def test_sort(self):
         for ind in self.indices.values():
             self.assertRaises(TypeError, ind.sort)
@@ -1695,9 +1704,10 @@ def test_reindexing(self):
 
     def test_duplicates(self):
 
-        idx = CategoricalIndex([0, 0, 0])
+        idx = CategoricalIndex([0, 0, 0],name='foo')
         self.assertFalse(idx.is_unique)
         self.assertTrue(idx.has_duplicates)
+        self.assertEqual(idx.name,'foo')
 
     def test_get_indexer(self):
 
@@ -4410,6 +4420,19 @@ def check(nlevels, with_nulls):
                 self.assert_array_equal(mi.duplicated(),
                                         np.zeros(len(mi), dtype='bool'))
 
+    def test_duplicate_meta_data(self):
+        # GH 10115
+        index = MultiIndex(levels=[[0, 1], [0, 1, 2]],
+                           labels=[[0, 0, 0, 0, 1, 1, 1],
+                                   [0, 1, 2, 0, 0, 1, 2]])
+        for idx in [index,
+                    index.set_names([None, None]),
+                    index.set_names([None, 'Num']),
+                    index.set_names(['Upper','Num']),
+                   ]:
+            self.assertTrue(idx.has_duplicates)
+            self.assertEqual(idx.drop_duplicates().names, idx.names)
+
     def test_tolist(self):
         result = self.index.tolist()
         exp = list(self.index.values)