BUG/TST: Address GH28283 calling __finalize__ in pivot_table, groupby.median and groupby.mean

doc/source/whatsnew/v1.3.0.rst

@@ -365,7 +365,7 @@ Reshaping
 - Bug in :meth:`DataFrame.join` not assigning values correctly when having :class:`MultiIndex` where at least one dimension is from dtype ``Categorical`` with non-alphabetically sorted categories (:issue:`38502`)
 - :meth:`Series.value_counts` returns keys in original order (:issue:`12679`, :issue:`11227`)
 - Bug in :meth:`DataFrame.apply` would give incorrect results when used with a string argument and ``axis=1`` when the axis argument was not supported and now raises a ``ValueError`` instead (:issue:`39211`)
--
+- Bug in :meth:`.GroupBy.mean`, :meth:`.GroupBy.median` and :meth:`DataFrame.pivot_table` not propagating metadata (:issue:`28283`)
 
 Sparse
 ^^^^^^

pandas/core/groupby/groupby.py

@@ -1513,11 +1513,12 @@ def mean(self, numeric_only: bool = True):
         2    4.0
         Name: B, dtype: float64
         """
-        return self._cython_agg_general(
+        result = self._cython_agg_general(
             "mean",
             alt=lambda x, axis: Series(x).mean(numeric_only=numeric_only),
             numeric_only=numeric_only,
         )
+        return result.__finalize__(self.obj, method="groupby")
 
     @final
     @Substitution(name="groupby")
@@ -1539,11 +1540,12 @@ def median(self, numeric_only=True):
         Series or DataFrame
             Median of values within each group.
         """
-        return self._cython_agg_general(
+        result = self._cython_agg_general(
             "median",
             alt=lambda x, axis: Series(x).median(axis=axis, numeric_only=numeric_only),
             numeric_only=numeric_only,
         )
+        return result.__finalize__(self.obj, method="groupby")
 
     @final
     @Substitution(name="groupby")

pandas/core/reshape/pivot.py

@@ -58,7 +58,7 @@ def pivot_table(
         pieces: List[DataFrame] = []
         keys = []
         for func in aggfunc:
-            table = pivot_table(
+            _table = _pivot_table(
                 data,
                 values=values,
                 index=index,
@@ -70,10 +70,39 @@ def pivot_table(
                 margins_name=margins_name,
                 observed=observed,
             )
-            pieces.append(table)
+            pieces.append(_table)
             keys.append(getattr(func, "__name__", func))
 
-        return concat(pieces, keys=keys, axis=1)
+        table = concat(pieces, keys=keys, axis=1)
+        return table.__finalize__(data, method="pivot_table")
+
+    table = _pivot_table(
+        data,
+        values,
+        index,
+        columns,
+        aggfunc,
+        fill_value,
+        margins,
+        dropna,
+        margins_name,
+        observed,
+    )
+    return table.__finalize__(data, method="pivot_table")
+
+
+def _pivot_table(
+    data,
+    values,
+    index,
+    columns,
+    aggfunc: str,
+    fill_value,
+    margins,
+    dropna,
+    margins_name,
+    observed,
+) -> DataFrame:
 
     keys = index + columns
 

pandas/tests/generic/test_finalize.py

@@ -149,13 +149,15 @@
         marks=not_implemented_mark,
     ),
     (pd.DataFrame, frame_data, operator.methodcaller("pivot", columns="A")),
-    pytest.param(
-        (
-            pd.DataFrame,
-            {"A": [1], "B": [1]},
-            operator.methodcaller("pivot_table", columns="A"),
-        ),
-        marks=not_implemented_mark,
+    (
+        pd.DataFrame,
+        ({"A": [1], "B": [1]},),
+        operator.methodcaller("pivot_table", columns="A"),
+    ),
+    (
+        pd.DataFrame,
+        ({"A": [1], "B": [1]},),
+        operator.methodcaller("pivot_table", columns="A", aggfunc=["mean", "sum"]),
     ),
     (pd.DataFrame, frame_data, operator.methodcaller("stack")),
     pytest.param(
@@ -740,6 +742,8 @@ def test_categorical_accessor(method):
     [
         operator.methodcaller("sum"),
         lambda x: x.agg("sum"),
+        lambda x: x.agg("mean"),
+        lambda x: x.agg("median"),
     ],
 )
 def test_groupby_finalize(obj, method):
@@ -757,6 +761,12 @@ def test_groupby_finalize(obj, method):
         lambda x: x.agg(["sum", "count"]),
         lambda x: x.transform(lambda y: y),
         lambda x: x.apply(lambda y: y),
+        lambda x: x.agg("std"),
+        lambda x: x.agg("var"),
+        lambda x: x.agg("sem"),
+        lambda x: x.agg("size"),
+        lambda x: x.agg("ohlc"),
+        lambda x: x.agg("describe"),
     ],
 )
 @not_implemented_mark