more indexing

Author: jreback

pandas/indexes/interval.py

@@ -514,13 +514,16 @@ def get_indexer(self, target, method=None, limit=None, tolerance=None):
                 raise ValueError('indexer corresponds to non-unique elements')
             return np.where(start_plus_one == stop, start, -1)
 
+        if isinstance(target, IntervalIndex):
+            raise NotImplementedError(
+                'have not yet implemented get_indexer '
+                'for IntervalIndex indexers')
+
+        if not self.is_unique:
+            indexer, missing = self._engine.get_indexer_non_unique(target.values)
         else:
-            if isinstance(target, IntervalIndex):
-                raise NotImplementedError(
-                    'have not yet implemented get_indexer '
-                    'for IntervalIndex indexers')
-            else:
-                return self._engine.get_indexer(target.values)
+            indexer = self._engine.get_indexer(target.values)
+        return indexer
 
     def sort_values(self, return_indexer=False, ascending=True):
         """

pandas/tests/indexing/test_interval.py

@@ -41,6 +41,28 @@ def test_loc_getitem_frame(self):
         expected = df.iloc[4:6]
         tm.assert_frame_equal(result, expected)
 
+        def f():
+            df.loc[10]
+
+        self.assertRaises(KeyError, f)
+
+        # single list-like
         result = df.loc[[4]]
         expected = df.iloc[4:6]
         tm.assert_frame_equal(result, expected)
+
+        # non-unique
+        result = df.loc[[4, 5]]
+        expected = df.take([4, 5, 4, 5])
+        tm.assert_frame_equal(result, expected)
+
+        def f():
+            df.loc[[10]]
+
+        self.assertRaises(KeyError, f)
+
+        # this is a bit different than other .loc indexing
+        def f():
+            df.loc[[10, 4]]
+
+        self.assertRaises(KeyError, f)