Fixed metadata propagation in DataFrame.__getitem__

doc/source/whatsnew/v1.2.0.rst

@@ -591,6 +591,7 @@ Other
 - Bug in :meth:`DataFrame.replace` and :meth:`Series.replace` incorrectly casting from ``PeriodDtype`` to object dtype (:issue:`34871`)
 - Fixed bug in metadata propagation incorrectly copying DataFrame columns as metadata when the column name overlaps with the metadata name (:issue:`37037`)
 - Fixed metadata propagation in the :class:`Series.dt`, :class:`Series.str` accessors, :class:`DataFrame.duplicated`, :class:`DataFrame.stack`, :class:`DataFrame.unstack`, :class:`DataFrame.pivot`, :class:`DataFrame.append`, :class:`DataFrame.diff`, :class:`DataFrame.applymap` and :class:`DataFrame.update` methods (:issue:`28283`) (:issue:`37381`)
+- Fixed metadata propagation when selecting columns from a DataFrame with ``DataFrame.__getitem__`` (:issue:`28283`)
 - Bug in :meth:`Index.union` behaving differently depending on whether operand is a :class:`Index` or other list-like (:issue:`36384`)
 - Passing an array with 2 or more dimensions to the :class:`Series` constructor now raises the more specific ``ValueError``, from a bare ``Exception`` previously (:issue:`35744`)
 - Bug in ``accessor.DirNamesMixin``, where ``dir(obj)`` wouldn't show attributes defined on the instance (:issue:`37173`).

pandas/core/generic.py

@@ -3777,7 +3777,7 @@ def _get_item_cache(self, item):
 
             loc = self.columns.get_loc(item)
             values = self._mgr.iget(loc)
-            res = self._box_col_values(values, loc)
+            res = self._box_col_values(values, loc).__finalize__(self)
 
             cache[item] = res
             res._set_as_cached(item, self)

pandas/tests/generic/test_duplicate_labels.py

@@ -312,9 +312,7 @@ def test_series_raises(self, func):
             pytest.param(
                 operator.itemgetter(("a", ["A", "A"])), "loc", marks=not_implemented
             ),
-            pytest.param(
-                operator.itemgetter((["a", "a"], "A")), "loc", marks=not_implemented
-            ),
+            (operator.itemgetter((["a", "a"], "A")), "loc"),
             # iloc
             (operator.itemgetter([0, 0]), "iloc"),
             pytest.param(

pandas/tests/generic/test_finalize.py

@@ -85,18 +85,12 @@
         marks=pytest.mark.xfail(reason="Implement binary finalize"),
     ),
     (pd.DataFrame, frame_data, operator.methodcaller("transpose")),
-    pytest.param(
-        (pd.DataFrame, frame_data, operator.methodcaller("__getitem__", "A")),
-        marks=not_implemented_mark,
-    ),
+    (pd.DataFrame, frame_data, operator.methodcaller("__getitem__", "A")),
     (pd.DataFrame, frame_data, operator.methodcaller("__getitem__", ["A"])),
     (pd.DataFrame, frame_data, operator.methodcaller("__getitem__", np.array([True]))),
     (pd.DataFrame, ({("A", "a"): [1]},), operator.methodcaller("__getitem__", ["A"])),
     (pd.DataFrame, frame_data, operator.methodcaller("query", "A == 1")),
-    pytest.param(
-        (pd.DataFrame, frame_data, operator.methodcaller("eval", "A + 1")),
-        marks=not_implemented_mark,
-    ),
+    (pd.DataFrame, frame_data, operator.methodcaller("eval", "A + 1", engine="python")),
     (pd.DataFrame, frame_data, operator.methodcaller("select_dtypes", include="int")),
     (pd.DataFrame, frame_data, operator.methodcaller("assign", b=1)),
     (pd.DataFrame, frame_data, operator.methodcaller("set_axis", ["A"])),
@@ -289,10 +283,7 @@
     ),
     (pd.DataFrame, frame_data, operator.methodcaller("swapaxes", 0, 1)),
     (pd.DataFrame, frame_mi_data, operator.methodcaller("droplevel", "A")),
-    pytest.param(
-        (pd.DataFrame, frame_data, operator.methodcaller("pop", "A")),
-        marks=not_implemented_mark,
-    ),
+    (pd.DataFrame, frame_data, operator.methodcaller("pop", "A")),
     pytest.param(
         (pd.DataFrame, frame_data, operator.methodcaller("squeeze")),
         marks=not_implemented_mark,
@@ -317,10 +308,7 @@
     (pd.DataFrame, frame_data, operator.methodcaller("take", [0, 0])),
     (pd.DataFrame, frame_mi_data, operator.methodcaller("xs", "a")),
     (pd.Series, (1, mi), operator.methodcaller("xs", "a")),
-    pytest.param(
-        (pd.DataFrame, frame_data, operator.methodcaller("get", "A")),
-        marks=not_implemented_mark,
-    ),
+    (pd.DataFrame, frame_data, operator.methodcaller("get", "A")),
     (
         pd.DataFrame,
         frame_data,
@@ -532,6 +520,15 @@ def test_finalize_called(ndframe_method):
     assert result.attrs == {"a": 1}
 
 
+@not_implemented_mark
+def test_finalize_called_eval_numexpr():
+    pytest.importorskip("numexpr")
+    df = pd.DataFrame({"A": [1, 2]})
+    df.attrs["A"] = 1
+    result = df.eval("A + 1", engine="numexpr")
+    assert result.attrs == {"A": 1}
+
+
 # ----------------------------------------------------------------------------
 # Binary operations