Merge pull request #6475 from jreback/td

BUG: Bug in sum of a timedelta64[ns] series (GH6462)

Author: jreback

doc/source/release.rst

@@ -175,6 +175,7 @@ Bug Fixes
 - Bug in ``str.extract`` when passed a non-default index (:issue:`6348`)
 - Bug in ``str.split`` when passed ``pat=None`` and ``n=1`` (:issue:`6466`)
 - Bug in ``io.data.DataReader`` when passed ``"F-F_Momentum_Factor"`` and ``data_source="famafrench"`` (:issue:`6460`)
+- Bug in ``sum`` of a ``timedelta64[ns]`` series (:issue:`6462`)
 
 pandas 0.13.1
 -------------

pandas/core/nanops.py

@@ -231,7 +231,8 @@ def nansum(values, axis=None, skipna=True):
     values, mask, dtype = _get_values(values, skipna, 0)
     the_sum = values.sum(axis)
     the_sum = _maybe_null_out(the_sum, axis, mask)
-    return the_sum
+
+    return _wrap_results(the_sum, dtype)
 
 
 @disallow('M8')

pandas/tseries/tests/test_timedeltas.py

@@ -207,6 +207,12 @@ def test_timedelta_ops(self):
         expected = to_timedelta('00:00:08')
         tm.assert_almost_equal(result, expected)
 
+        # GH 6462
+        # consistency in returned values for sum
+        result = td.sum()[0]
+        expected = to_timedelta('00:01:21')
+        tm.assert_almost_equal(result, expected)
+
     def test_to_timedelta_on_missing_values(self):
         _skip_if_numpy_not_friendly()