diff --git a/doc/source/whatsnew/v1.1.0.rst b/doc/source/whatsnew/v1.1.0.rst index b9ef1aae9a801..52b19fd4ebf2e 100644 --- a/doc/source/whatsnew/v1.1.0.rst +++ b/doc/source/whatsnew/v1.1.0.rst @@ -1117,6 +1117,7 @@ Groupby/resample/rolling - Bug in :meth:`DataFrame.ewm.cov` was throwing ``AssertionError`` for :class:`MultiIndex` inputs (:issue:`34440`) - Bug in :meth:`core.groupby.DataFrameGroupBy.quantile` raises ``TypeError`` for non-numeric types rather than dropping columns (:issue:`27892`) - Bug in :meth:`core.groupby.DataFrameGroupBy.transform` when ``func='nunique'`` and columns are of type ``datetime64``, the result would also be of type ``datetime64`` instead of ``int64`` (:issue:`35109`) +- Bug in :meth:`DataFrame.groupby` raising an ``AttributeError`` when selecting a column and aggregating with ``as_index=False`` (:issue:`35246`). - Bug in :meth:'DataFrameGroupBy.first' and :meth:'DataFrameGroupBy.last' that would raise an unnecessary ``ValueError`` when grouping on multiple ``Categoricals`` (:issue:`34951`) Reshaping diff --git a/pandas/core/groupby/generic.py b/pandas/core/groupby/generic.py index 1d14361757e4a..ec7b14f27c5a1 100644 --- a/pandas/core/groupby/generic.py +++ b/pandas/core/groupby/generic.py @@ -963,18 +963,23 @@ def aggregate(self, func=None, *args, engine=None, engine_kwargs=None, **kwargs) # try to treat as if we are passing a list try: result = self._aggregate_multiple_funcs([func], _axis=self.axis) - except ValueError as err: - if "no results" not in str(err): - # raised directly by _aggregate_multiple_funcs - raise - result = self._aggregate_frame(func) - else: + # select everything except for the last level, which is the one # containing the name of the function(s), see GH 32040 result.columns = result.columns.rename( [self._selected_obj.columns.name] * result.columns.nlevels ).droplevel(-1) + except ValueError as err: + if "no results" not in str(err): + # raised directly by _aggregate_multiple_funcs + raise + result = self._aggregate_frame(func) + except AttributeError: + # catch exception from line 969 + # (Series does not have attribute "columns"), see GH 35246 + result = self._aggregate_frame(func) + if relabeling: # used reordered index of columns diff --git a/pandas/tests/groupby/test_groupby.py b/pandas/tests/groupby/test_groupby.py index 0d040b8e6955a..ebce5b0ef0a66 100644 --- a/pandas/tests/groupby/test_groupby.py +++ b/pandas/tests/groupby/test_groupby.py @@ -605,6 +605,14 @@ def test_as_index_select_column(): tm.assert_series_equal(result, expected) +def test_groupby_as_index_select_column_sum_empty_df(): + # GH 35246 + df = DataFrame(columns=["A", "B", "C"]) + left = df.groupby(by="A", as_index=False)["B"].sum() + assert type(left) is DataFrame + assert left.to_dict() == {"A": {}, "B": {}} + + def test_groupby_as_index_agg(df): grouped = df.groupby("A", as_index=False)