diff --git a/doc/source/whatsnew/v1.1.4.rst b/doc/source/whatsnew/v1.1.4.rst index 6892fb62028c9..1abaf28e14af0 100644 --- a/doc/source/whatsnew/v1.1.4.rst +++ b/doc/source/whatsnew/v1.1.4.rst @@ -20,6 +20,7 @@ Fixed regressions - Fixed regression in :class:`RollingGroupby` with ``sort=False`` not being respected (:issue:`36889`) - Fixed regression in :meth:`Series.astype` converting ``None`` to ``"nan"`` when casting to string (:issue:`36904`) - Fixed regression in :class:`RollingGroupby` causing a segmentation fault with Index of dtype object (:issue:`36727`) +- Fixed regression in :meth:`DataFrame.resample(...).apply(...)` raised ``AttributeError`` when input was a :class:`DataFrame` and only a :class:`Series` was evaluated (:issue:`36951`) .. --------------------------------------------------------------------------- diff --git a/pandas/core/resample.py b/pandas/core/resample.py index 3f1b1dac080a7..caef938272f6f 100644 --- a/pandas/core/resample.py +++ b/pandas/core/resample.py @@ -369,8 +369,9 @@ def _groupby_and_aggregate(self, how, grouper=None, *args, **kwargs): result = grouped._aggregate_item_by_item(how, *args, **kwargs) else: result = grouped.aggregate(how, *args, **kwargs) - except DataError: + except (DataError, AttributeError, KeyError): # we have a non-reducing function; try to evaluate + # alternatively we want to evaluate only a column of the input result = grouped.apply(how, *args, **kwargs) except ValueError as err: if "Must produce aggregated value" in str(err): diff --git a/pandas/tests/resample/test_resampler_grouper.py b/pandas/tests/resample/test_resampler_grouper.py index 73bf7dafac254..2f22be7c8cce9 100644 --- a/pandas/tests/resample/test_resampler_grouper.py +++ b/pandas/tests/resample/test_resampler_grouper.py @@ -347,3 +347,18 @@ def test_median_duplicate_columns(): result = df.resample("5s").median() expected.columns = result.columns tm.assert_frame_equal(result, expected) + + +def test_apply_to_one_column_of_df(): + # GH: 36951 + df = pd.DataFrame( + {"col": range(10), "col1": range(10, 20)}, + index=pd.date_range("2012-01-01", periods=10, freq="20min"), + ) + result = df.resample("H").apply(lambda group: group.col.sum()) + expected = pd.Series( + [3, 12, 21, 9], index=pd.date_range("2012-01-01", periods=4, freq="H") + ) + tm.assert_series_equal(result, expected) + result = df.resample("H").apply(lambda group: group["col"].sum()) + tm.assert_series_equal(result, expected)