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BUG: DataFrame.shift shows different behavior for axis=1 when freq is specified #47051

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May 28, 2022
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1 change: 1 addition & 0 deletions doc/source/whatsnew/v1.4.3.rst
Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,7 @@ Fixed regressions
- Fixed regression in :func:`read_csv` with ``index_col=False`` identifying first row as index names when ``header=None`` (:issue:`46955`)
- Fixed regression in :meth:`.DataFrameGroupBy.agg` when used with list-likes or dict-likes and ``axis=1`` that would give incorrect results; now raises ``NotImplementedError`` (:issue:`46995`)
- Fixed regression in :meth:`DataFrame.resample` and :meth:`DataFrame.rolling` when used with list-likes or dict-likes and ``axis=1`` that would raise an unintuitive error message; now raises ``NotImplementedError`` (:issue:`46904`)
- Fixed regression in :meth:`DataFrame.shift` when ``axis`` is ``columns`` and ``fill_value`` is absent, ``freq`` is ignored (:issue:`47039`)

.. ---------------------------------------------------------------------------

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8 changes: 7 additions & 1 deletion pandas/core/frame.py
Original file line number Diff line number Diff line change
Expand Up @@ -5506,7 +5506,13 @@ def shift(
axis = self._get_axis_number(axis)

ncols = len(self.columns)
if axis == 1 and periods != 0 and fill_value is lib.no_default and ncols > 0:
if (
axis == 1
and periods != 0
and freq is None
and fill_value is lib.no_default
and ncols > 0
):
# We will infer fill_value to match the closest column

# Use a column that we know is valid for our column's dtype GH#38434
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10 changes: 10 additions & 0 deletions pandas/tests/frame/methods/test_shift.py
Original file line number Diff line number Diff line change
Expand Up @@ -259,6 +259,16 @@ def test_shift_named_axis(self):
result = df.shift(1, axis="columns")
tm.assert_frame_equal(result, expected)

def test_shift_other_axis_with_freq(self, datetime_frame):
obj = datetime_frame.T
offset = offsets.BDay()

# GH#47039
shifted = obj.shift(5, freq=offset, axis=1)
assert len(shifted) == len(obj)
unshifted = shifted.shift(-5, freq=offset, axis=1)
tm.assert_equal(unshifted, obj)

def test_shift_bool(self):
df = DataFrame({"high": [True, False], "low": [False, False]})
rs = df.shift(1)
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