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Revert "REF: move shift logic from BlockManager to DataFrame (#40536)" (#42317)
This reverts commit 9535280.
1 parent 12513c4 commit 027d374

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3 files changed

+44
-35
lines changed

3 files changed

+44
-35
lines changed

pandas/core/frame.py

+17-34
Original file line numberDiff line numberDiff line change
@@ -5279,45 +5279,28 @@ def shift(
52795279
axis = self._get_axis_number(axis)
52805280

52815281
ncols = len(self.columns)
5282+
if axis == 1 and periods != 0 and fill_value is lib.no_default and ncols > 0:
5283+
# We will infer fill_value to match the closest column
52825284

5283-
if (
5284-
axis == 1
5285-
and periods != 0
5286-
and ncols > 0
5287-
and (fill_value is lib.no_default or len(self._mgr.arrays) > 1)
5288-
):
5289-
# Exclude single-array-with-fill_value case so we issue a FutureWarning
5290-
# if an integer is passed with datetimelike dtype GH#31971
5291-
from pandas import concat
5285+
# Use a column that we know is valid for our column's dtype GH#38434
5286+
label = self.columns[0]
52925287

5293-
# tail: the data that is still in our shifted DataFrame
52945288
if periods > 0:
5295-
tail = self.iloc[:, :-periods]
5296-
else:
5297-
tail = self.iloc[:, -periods:]
5298-
# pin a simple Index to avoid costly casting
5299-
tail.columns = range(len(tail.columns))
5300-
5301-
if fill_value is not lib.no_default:
5302-
# GH#35488
5303-
# TODO(EA2D): with 2D EAs we could construct other directly
5304-
ser = Series(fill_value, index=self.index)
5289+
result = self.iloc[:, :-periods]
5290+
for col in range(min(ncols, abs(periods))):
5291+
# TODO(EA2D): doing this in a loop unnecessary with 2D EAs
5292+
# Define filler inside loop so we get a copy
5293+
filler = self.iloc[:, 0].shift(len(self))
5294+
result.insert(0, label, filler, allow_duplicates=True)
53055295
else:
5306-
# We infer fill_value to match the closest column
5307-
if periods > 0:
5308-
ser = self.iloc[:, 0].shift(len(self))
5309-
else:
5310-
ser = self.iloc[:, -1].shift(len(self))
5311-
5312-
width = min(abs(periods), ncols)
5313-
other = concat([ser] * width, axis=1)
5314-
5315-
if periods > 0:
5316-
result = concat([other, tail], axis=1)
5317-
else:
5318-
result = concat([tail, other], axis=1)
5296+
result = self.iloc[:, -periods:]
5297+
for col in range(min(ncols, abs(periods))):
5298+
# Define filler inside loop so we get a copy
5299+
filler = self.iloc[:, -1].shift(len(self))
5300+
result.insert(
5301+
len(result.columns), label, filler, allow_duplicates=True
5302+
)
53195303

5320-
result = cast(DataFrame, result)
53215304
result.columns = self.columns.copy()
53225305
return result
53235306

pandas/core/internals/managers.py

+19
Original file line numberDiff line numberDiff line change
@@ -381,6 +381,25 @@ def shift(self: T, periods: int, axis: int, fill_value) -> T:
381381
if fill_value is lib.no_default:
382382
fill_value = None
383383

384+
if axis == 0 and self.ndim == 2 and self.nblocks > 1:
385+
# GH#35488 we need to watch out for multi-block cases
386+
# We only get here with fill_value not-lib.no_default
387+
ncols = self.shape[0]
388+
if periods > 0:
389+
indexer = [-1] * periods + list(range(ncols - periods))
390+
else:
391+
nper = abs(periods)
392+
indexer = list(range(nper, ncols)) + [-1] * nper
393+
result = self.reindex_indexer(
394+
self.items,
395+
indexer,
396+
axis=0,
397+
fill_value=fill_value,
398+
allow_dups=True,
399+
consolidate=False,
400+
)
401+
return result
402+
384403
return self.apply("shift", periods=periods, axis=axis, fill_value=fill_value)
385404

386405
def fillna(self: T, value, limit, inplace: bool, downcast) -> T:

pandas/tests/apply/test_frame_transform.py

+8-1
Original file line numberDiff line numberDiff line change
@@ -39,8 +39,15 @@ def test_transform_ufunc(axis, float_frame, frame_or_series):
3939

4040

4141
@pytest.mark.parametrize("op", frame_transform_kernels)
42-
def test_transform_groupby_kernel(axis, float_frame, op, request):
42+
def test_transform_groupby_kernel(axis, float_frame, op, using_array_manager, request):
4343
# GH 35964
44+
if using_array_manager and op == "pct_change" and axis in (1, "columns"):
45+
# TODO(ArrayManager) shift with axis=1
46+
request.node.add_marker(
47+
pytest.mark.xfail(
48+
reason="shift axis=1 not yet implemented for ArrayManager"
49+
)
50+
)
4451

4552
args = [0.0] if op == "fillna" else []
4653
if axis == 0 or axis == "index":

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