Merge pull request #5772 from jreback/series_loc

BUG: setitem for iloc/loc with a slice on a Series (GH5771)

Author: jreback

pandas/core/indexing.py

@@ -420,7 +420,10 @@ def can_do_equal_len():
             self.obj._maybe_update_cacher(clear=True)
 
     def _align_series(self, indexer, ser):
-        # indexer to assign Series can be tuple or scalar
+        # indexer to assign Series can be tuple, slice, scalar
+        if isinstance(indexer, slice):
+            indexer = tuple([indexer])
+
         if isinstance(indexer, tuple):
 
             aligners = [not _is_null_slice(idx) for idx in indexer]

pandas/tests/test_indexing.py

@@ -456,6 +456,20 @@ def test_iloc_setitem(self):
         result = df.iloc[:,2:3]
         assert_frame_equal(result, expected)
 
+        # GH5771
+        s = Series(0,index=[4,5,6])
+        s.iloc[1:2] += 1
+        expected = Series([0,1,0],index=[4,5,6])
+        assert_series_equal(s, expected)
+
+    def test_loc_setitem(self):
+        # GH 5771
+        # loc with slice and series
+        s = Series(0,index=[4,5,6])
+        s.loc[4:5] += 1
+        expected = Series([1,1,0],index=[4,5,6])
+        assert_series_equal(s, expected)
+
     def test_loc_getitem_int(self):
 
         # int label