BUG: label slicing with duplicate values, close #1480

Author: wesm

pandas/core/indexing.py

@@ -341,6 +341,10 @@ def _convert_to_indexer(self, obj, axis=0):
             else:
                 try:
                     i, j = labels.slice_locs(start, stop)
+                    if isinstance(i, slice):
+                        i = i.start
+                    if isinstance(j, slice):
+                        j = j.stop
                     slicer = slice(i, j, obj.step)
                 except Exception:
                     if _is_index_slice(obj):

pandas/tseries/tests/test_timeseries.py

@@ -79,6 +79,20 @@ def test_duplicate_dates_indexing(self):
         self.assertRaises(KeyError, ts.__getitem__, datetime(2000, 1, 6))
         self.assertRaises(KeyError, ts.__setitem__, datetime(2000, 1, 6), 0)
 
+    def test_range_slice(self):
+        idx = DatetimeIndex(['1/1/2000', '1/2/2000', '1/2/2000', '1/3/2000',
+                             '1/4/2000'])
+
+        ts = Series(np.random.randn(len(idx)), index=idx)
+
+        result = ts['1/2/2000':]
+        expected = ts[1:]
+        assert_series_equal(result, expected)
+
+        result = ts['1/2/2000':'1/3/2000']
+        expected = ts[1:4]
+        assert_series_equal(result, expected)
+
     def test_groupby_average_dup_values(self):
         result = self.dups.groupby(level=0).mean()
         expected = self.dups.groupby(self.dups.index).mean()