BUG: Fix indexing on DatetimeBlock

doc/source/whatsnew/v0.25.0.rst

@@ -743,7 +743,8 @@ Indexing
 - Bug in which :meth:`DataFrame.to_csv` caused a segfault for a reindexed data frame, when the indices were single-level :class:`MultiIndex` (:issue:`26303`).
 - Fixed bug where assigning a :class:`arrays.PandasArray` to a :class:`pandas.core.frame.DataFrame` would raise error (:issue:`26390`)
 - Allow keyword arguments for callable local reference used in the :meth:`DataFrame.query` string (:issue:`26426`)
-
+- Bug in :method:`DataFrame.loc` and :method:`DataFrame.iloc` on a :class:`DataFrame` with a single timezone-aware datetime64[ns] column incorrectly returning a scalar instead of a :class:`Series` (:issue:`27110`)
+-
 
 Missing
 ^^^^^^^

pandas/core/internals/blocks.py

@@ -1539,6 +1539,10 @@ def iget(self, col):
             col, loc = col
             if not com.is_null_slice(col) and col != 0:
                 raise IndexError("{0} only contains one item".format(self))
+            if isinstance(col, slice):
+                if col != slice(None):
+                    raise NotImplementedError(col)
+                return self.values[[loc]]
             return self.values[loc]
         else:
             if col != 0:

pandas/tests/groupby/aggregate/test_other.py

@@ -421,11 +421,12 @@ def test_agg_timezone_round_trip():
     assert ts == grouped.nth(0)['B'].iloc[0]
     assert ts == grouped.head(1)['B'].iloc[0]
     assert ts == grouped.first()['B'].iloc[0]
-    assert ts == grouped.apply(lambda x: x.iloc[0])[0]
+    assert ts == grouped.apply(lambda x: x.iloc[0]).iloc[0, 0]
 
     ts = df['B'].iloc[2]
     assert ts == grouped.last()['B'].iloc[0]
-    assert ts == grouped.apply(lambda x: x.iloc[-1])[0]
+    # FIXME: the next assertion is wrong; GH#26864
+    assert ts == grouped.apply(lambda x: x.iloc[-1]).iloc[0, 0]
 
 
 def test_sum_uint64_overflow():

pandas/tests/indexing/test_datetime.py

@@ -39,7 +39,7 @@ def test_setitem_with_datetime_tz(self):
 
     def test_indexing_with_datetime_tz(self):
 
-        # 8260
+        # GH#8260
         # support datetime64 with tz
 
         idx = Index(date_range('20130101', periods=3, tz='US/Eastern'),
@@ -65,11 +65,12 @@ def test_indexing_with_datetime_tz(self):
         # indexing - fast_xs
         df = DataFrame({'a': date_range('2014-01-01', periods=10, tz='UTC')})
         result = df.iloc[5]
-        expected = Timestamp('2014-01-06 00:00:00+0000', tz='UTC', freq='D')
-        assert result == expected
+        expected = Series([Timestamp('2014-01-06 00:00:00+0000', tz='UTC')],
+                          index=['a'], name=5)
+        tm.assert_series_equal(result, expected)
 
         result = df.loc[5]
-        assert result == expected
+        tm.assert_series_equal(result, expected)
 
         # indexing - boolean
         result = df[df.a > df.a[3]]