ENH: convert to TimeSeries when setting a DatetimeIndex. close #2139

Author: wesm

pandas/core/series.py

@@ -368,6 +368,10 @@ def __new__(cls, data=None, index=None, dtype=None, name=None,
 
         return subarr
 
+    def _make_time_series(self):
+        # oh boy #2139
+        self.__class__ = TimeSeries
+
     @classmethod
     def from_array(cls, arr, index=None, name=None, copy=False):
         """

pandas/sparse/series.py

@@ -155,6 +155,10 @@ def __new__(cls, data, index=None, sparse_index=None, kind='block',
         output.name = name
         return output
 
+    def _make_time_series(self):
+        # oh boy #2139
+        self.__class__ = SparseTimeSeries
+
     @classmethod
     def from_array(cls, arr, index=None, name=None, copy=False,fill_value=None):
         """

pandas/src/properties.pyx

@@ -57,7 +57,11 @@ cdef class SeriesIndex(object):
     def __set__(self, obj, value):
         if len(obj) != len(value):
             raise AssertionError('Index length did not match values')
-        obj._index = self._check_type(value)
+        obj._index = val = self._check_type(value)
+        if hasattr(val, 'tz'):
+            # hack for #2139
+            obj._make_time_series()
+
 
 cdef class ValuesProperty(object):
 

pandas/tests/test_series.py

@@ -3345,6 +3345,14 @@ def test_reset_index(self):
         self.assert_(rs.index.equals(Index(index.get_level_values(1))))
         self.assert_(isinstance(rs, Series))
 
+    def test_set_index_makes_timeseries(self):
+        idx = tm.makeDateIndex(10)
+
+        s = Series(range(10))
+        s.index = idx
+
+        self.assertTrue(isinstance(s, TimeSeries))
+
     def test_timeseries_coercion(self):
         idx = tm.makeDateIndex(10000)
         ser = Series(np.random.randn(len(idx)), idx.astype(object))