Fixed loffset with numpy timedelta (#22482)

Author: discort

doc/source/whatsnew/v0.24.0.txt

@@ -707,6 +707,7 @@ Groupby/Resample/Rolling
 - Multiple bugs in :func:`pandas.core.Rolling.min` with ``closed='left'` and a
  datetime-like index leading to incorrect results and also segfault. (:issue:`21704`)
 - Bug in :meth:`Resampler.apply` when passing postiional arguments to applied func (:issue:`14615`).
+- Bug in :meth:`Series.resample` when passing ``numpy.timedelta64`` to `loffset` kwarg (:issue:`7687`).
 
 Sparse
 ^^^^^^

pandas/core/resample.py

@@ -366,7 +366,8 @@ def _apply_loffset(self, result):
  """
 
  needs_offset = (
- isinstance(self.loffset, (DateOffset, timedelta)) and
+ isinstance(self.loffset, (DateOffset, timedelta,
+ np.timedelta64)) and
  isinstance(result.index, DatetimeIndex) and
  len(result.index) > 0
  )

pandas/tests/test_resample.py

@@ -1173,27 +1173,20 @@ def test_resample_frame_basic(self):
  df.resample('M', kind='period').mean()
  df.resample('W-WED', kind='period').mean()
 
- def test_resample_loffset(self):
+ @pytest.mark.parametrize('loffset', [timedelta(minutes=1),
+ '1min', Minute(1),
+ np.timedelta64(1, 'm')])
+ def test_resample_loffset(self, loffset):
+ # GH 7687
  rng = date_range('1/1/2000 00:00:00', '1/1/2000 00:13:00', freq='min')
  s = Series(np.random.randn(14), index=rng)
 
  result = s.resample('5min', closed='right', label='right',
- loffset=timedelta(minutes=1)).mean()
+ loffset=loffset).mean()
  idx = date_range('1/1/2000', periods=4, freq='5min')
  expected = Series([s[0], s[1:6].mean(), s[6:11].mean(), s[11:].mean()],
  index=idx + timedelta(minutes=1))
  assert_series_equal(result, expected)
-
- expected = s.resample(
- '5min', closed='right', label='right',
- loffset='1min').mean()
- assert_series_equal(result, expected)
-
- expected = s.resample(
- '5min', closed='right', label='right',
- loffset=Minute(1)).mean()
- assert_series_equal(result, expected)
-
  assert result.index.freq == Minute(5)
 
  # from daily