BUG: fix reindexing with a tz-aware index and method='nearest' (#31511)

Author: kandersolar

doc/source/whatsnew/v1.1.0.rst

@@ -108,6 +108,7 @@ Datetimelike
 - Bug in :class:`Timestamp` where constructing :class:`Timestamp` from ambiguous epoch time and calling constructor again changed :meth:`Timestamp.value` property (:issue:`24329`)
 - :meth:`DatetimeArray.searchsorted`, :meth:`TimedeltaArray.searchsorted`, :meth:`PeriodArray.searchsorted` not recognizing non-pandas scalars and incorrectly raising ``ValueError`` instead of ``TypeError`` (:issue:`30950`)
 - Bug in :class:`Timestamp` where constructing :class:`Timestamp` with dateutil timezone less than 128 nanoseconds before daylight saving time switch from winter to summer would result in nonexistent time (:issue:`31043`)
+- Bug in :meth:`DataFrame.reindex` and :meth:`Series.reindex` when reindexing with a tz-aware index (:issue:`26683`)
 
 Timedelta
 ^^^^^^^^^
@@ -154,7 +155,6 @@ Indexing
 - Bug in :meth:`Series.at` and :meth:`DataFrame.at` not matching ``.loc`` behavior when looking up an integer in a :class:`Float64Index` (:issue:`31329`)
 - Bug in :meth:`PeriodIndex.is_monotonic` incorrectly returning ``True`` when containing leading ``NaT`` entries (:issue:`31437`)
 - Bug in :meth:`DatetimeIndex.get_loc` raising ``KeyError`` with converted-integer key instead of the user-passed key (:issue:`31425`)
--
 
 Missing
 ^^^^^^^

pandas/core/indexes/base.py

@@ -3073,9 +3073,8 @@ def _get_nearest_indexer(self, target: "Index", limit, tolerance) -> np.ndarray:
  left_indexer = self.get_indexer(target, "pad", limit=limit)
  right_indexer = self.get_indexer(target, "backfill", limit=limit)
 
- target = np.asarray(target)
- left_distances = abs(self.values[left_indexer] - target)
- right_distances = abs(self.values[right_indexer] - target)
+ left_distances = np.abs(self[left_indexer] - target)
+ right_distances = np.abs(self[right_indexer] - target)
 
  op = operator.lt if self.is_monotonic_increasing else operator.le
  indexer = np.where(

pandas/tests/frame/indexing/test_indexing.py

@@ -1602,6 +1602,16 @@ def test_reindex_methods_nearest_special(self):
  actual = df.reindex(target, method="nearest", tolerance=[0.5, 0.01, 0.4, 0.1])
  tm.assert_frame_equal(expected, actual)
 
+ def test_reindex_nearest_tz(self, tz_aware_fixture):
+ # GH26683
+ tz = tz_aware_fixture
+ idx = pd.date_range("2019-01-01", periods=5, tz=tz)
+ df = pd.DataFrame({"x": list(range(5))}, index=idx)
+
+ expected = df.head(3)
+ actual = df.reindex(idx[:3], method="nearest")
+ tm.assert_frame_equal(expected, actual)
+
  def test_reindex_frame_add_nat(self):
  rng = date_range("1/1/2000 00:00:00", periods=10, freq="10s")
  df = DataFrame({"A": np.random.randn(len(rng)), "B": rng})