Preserve name for DatetimeIndex field accessors

Author: jorisvandenbossche

pandas/tests/indexes/datetimes/test_misc.py

@@ -230,24 +230,18 @@ def test_datetimeindex_accessors(self):
         self.assertEqual(Timestamp('2016-04-09').weekday_name, u'Saturday')
         self.assertEqual(Timestamp('2016-04-10').weekday_name, u'Sunday')
 
-        self.assertEqual(len(dti.year), 365)
-        self.assertEqual(len(dti.month), 365)
-        self.assertEqual(len(dti.day), 365)
-        self.assertEqual(len(dti.hour), 365)
-        self.assertEqual(len(dti.minute), 365)
-        self.assertEqual(len(dti.second), 365)
-        self.assertEqual(len(dti.microsecond), 365)
-        self.assertEqual(len(dti.dayofweek), 365)
-        self.assertEqual(len(dti.dayofyear), 365)
-        self.assertEqual(len(dti.weekofyear), 365)
-        self.assertEqual(len(dti.quarter), 365)
-        self.assertEqual(len(dti.is_month_start), 365)
-        self.assertEqual(len(dti.is_month_end), 365)
-        self.assertEqual(len(dti.is_quarter_start), 365)
-        self.assertEqual(len(dti.is_quarter_end), 365)
-        self.assertEqual(len(dti.is_year_start), 365)
-        self.assertEqual(len(dti.is_year_end), 365)
-        self.assertEqual(len(dti.weekday_name), 365)
+        dti.name = 'name'
+
+        for accessor in ['year', 'month', 'day', 'hour', 'minute', 'second',
+                         'microsecond', 'nanosecond', 'dayofweek', 'dayofyear',
+                         'weekofyear', 'quarter',
+                         'is_month_start', 'is_month_end',
+                         'is_quarter_start', 'is_quarter_end',
+                         'is_year_start', 'is_year_end', 'weekday_name']:
+            res = getattr(dti, accessor)
+            self.assertEqual(len(res), 365)
+            self.assertIsInstance(res, Index)
+            self.assertEqual(res.name, 'name')
 
         dti = DatetimeIndex(freq='BQ-FEB', start=datetime(1998, 1, 1),
                             periods=4)

pandas/tseries/index.py

@@ -89,7 +89,7 @@ def f(self):
             result = tslib.get_date_field(values, field)
             result = self._maybe_mask_results(result, convert='float64')
 
-        return Index(result)
+        return Index(result, name=self.name)
 
     f.__name__ = name
     f.__doc__ = docstring