Add missing __finalize__ calls in indexers/iterators (#46101)

Author: theOehrly

doc/source/whatsnew/v1.5.0.rst

@@ -542,6 +542,7 @@ Indexing
 - Bug in :meth:`CategoricalIndex.get_indexer` when index contains ``NaN`` values, resulting in elements that are in target but not present in the index to be mapped to the index of the NaN element, instead of -1 (:issue:`45361`)
 - Bug in setting large integer values into :class:`Series` with ``float32`` or ``float16`` dtype incorrectly altering these values instead of coercing to ``float64`` dtype (:issue:`45844`)
 - Bug in :meth:`Series.asof` and :meth:`DataFrame.asof` incorrectly casting bool-dtype results to ``float64`` dtype (:issue:`16063`)
+- Bug in :meth:`NDFrame.xs`, :meth:`DataFrame.iterrows`, :meth:`DataFrame.loc` and :meth:`DataFrame.iloc` not always propagating metadata (:issue:`28283`)
 -
 
 Missing

pandas/core/frame.py

@@ -1339,7 +1339,7 @@ def iterrows(self) -> Iterable[tuple[Hashable, Series]]:
         columns = self.columns
         klass = self._constructor_sliced
         for k, v in zip(self.index, self.values):
-            s = klass(v, index=columns, name=k)
+            s = klass(v, index=columns, name=k).__finalize__(self)
             yield k, s
 
     def itertuples(
@@ -3455,7 +3455,7 @@ def _ixs(self, i: int, axis: int = 0):
                 index=self.columns,
                 name=self.index[i],
                 dtype=new_values.dtype,
-            )
+            ).__finalize__(self)
             result._set_is_copy(self, copy=copy)
             return result
 

pandas/core/generic.py

@@ -3816,7 +3816,7 @@ class   animal   locomotion
                 index=self.columns,
                 name=self.index[loc],
                 dtype=new_values.dtype,
-            )
+            ).__finalize__(self)
         elif is_scalar(loc):
             result = self.iloc[:, slice(loc, loc + 1)]
         elif axis == 1:

pandas/tests/generic/test_duplicate_labels.py

@@ -84,7 +84,6 @@ def test_binops(self, func, other, frame):
         assert df.flags.allows_duplicate_labels is False
         assert func(df).flags.allows_duplicate_labels is False
 
-    @not_implemented
     def test_preserve_getitem(self):
         df = pd.DataFrame({"A": [1, 2]}).set_flags(allows_duplicate_labels=False)
         assert df[["A"]].flags.allows_duplicate_labels is False
@@ -306,15 +305,11 @@ def test_series_raises(self):
             (operator.itemgetter(["A", "A"]), None),
             # loc
             (operator.itemgetter(["a", "a"]), "loc"),
-            pytest.param(
-                operator.itemgetter(("a", ["A", "A"])), "loc", marks=not_implemented
-            ),
+            pytest.param(operator.itemgetter(("a", ["A", "A"])), "loc"),
             (operator.itemgetter((["a", "a"], "A")), "loc"),
             # iloc
             (operator.itemgetter([0, 0]), "iloc"),
-            pytest.param(
-                operator.itemgetter((0, [0, 0])), "iloc", marks=not_implemented
-            ),
+            pytest.param(operator.itemgetter((0, [0, 0])), "iloc"),
             pytest.param(operator.itemgetter(([0, 0], 0)), "iloc"),
         ],
     )

pandas/tests/generic/test_finalize.py

@@ -247,7 +247,6 @@
             frame_data,
             operator.methodcaller("quantile", numeric_only=True),
         ),
-        marks=not_implemented_mark,
     ),
     pytest.param(
         (
@@ -259,10 +258,9 @@
     pytest.param(
         (
             pd.DataFrame,
-            frame_data,
-            operator.methodcaller("quantile", numeric_only=True),
+            ({"A": [pd.Timedelta(days=1), pd.Timedelta(days=2)]},),
+            operator.methodcaller("quantile", numeric_only=False),
         ),
-        marks=not_implemented_mark,
     ),
     (
         pd.DataFrame,