REGR: fix DataFrame reduction with EA columns and numeric_only=True (#33761)

Author: jorisvandenbossche

doc/source/whatsnew/v1.1.0.rst

@@ -572,6 +572,7 @@ Numeric
 - Bug in :meth:`DataFrame.mean` with ``numeric_only=False`` and either ``datetime64`` dtype or ``PeriodDtype`` column incorrectly raising ``TypeError`` (:issue:`32426`)
 - Bug in :meth:`DataFrame.count` with ``level="foo"`` and index level ``"foo"`` containing NaNs causes segmentation fault (:issue:`21824`)
 - Bug in :meth:`DataFrame.diff` with ``axis=1`` returning incorrect results with mixed dtypes (:issue:`32995`)
+- Bug in DataFrame reductions using ``numeric_only=True`` and ExtensionArrays (:issue:`33256`).
 - Bug in :meth:`DataFrame.corr` and :meth:`DataFrame.cov` raising when handling nullable integer columns with ``pandas.NA`` (:issue:`33803`)
 - Bug in :class:`DataFrame` and :class:`Series` addition and subtraction between object-dtype objects and ``datetime64`` dtype objects (:issue:`33824`)
 

pandas/core/frame.py

@@ -8325,10 +8325,10 @@ def _get_data(axis_matters):
             out_dtype = "bool" if filter_type == "bool" else None
 
             def blk_func(values):
-                if values.ndim == 1 and not isinstance(values, np.ndarray):
-                    # we can't pass axis=1
-                    return op(values, axis=0, skipna=skipna, **kwds)
-                return op(values, axis=1, skipna=skipna, **kwds)
+                if isinstance(values, ExtensionArray):
+                    return values._reduce(name, skipna=skipna, **kwds)
+                else:
+                    return op(values, axis=1, skipna=skipna, **kwds)
 
             # After possibly _get_data and transposing, we are now in the
             #  simple case where we can use BlockManager._reduce

pandas/tests/frame/test_analytics.py

@@ -896,9 +896,17 @@ def test_mean_datetimelike_numeric_only_false(self):
         # mean of period is not allowed
         df["D"] = pd.period_range("2016", periods=3, freq="A")
 
-        with pytest.raises(TypeError, match="reduction operation 'mean' not allowed"):
+        with pytest.raises(TypeError, match="mean is not implemented for Period"):
             df.mean(numeric_only=False)
 
+    def test_mean_extensionarray_numeric_only_true(self):
+        # https://github.com/pandas-dev/pandas/issues/33256
+        arr = np.random.randint(1000, size=(10, 5))
+        df = pd.DataFrame(arr, dtype="Int64")
+        result = df.mean(numeric_only=True)
+        expected = pd.DataFrame(arr).mean()
+        tm.assert_series_equal(result, expected)
+
     def test_stats_mixed_type(self, float_string_frame):
         # don't blow up
         float_string_frame.std(1)