_get_sliced_frame_result_type

to check type of DataFrame._constructor_sliced

pandas/core/dtypes/concat.py

@@ -101,6 +101,18 @@ def _get_frame_result_type(result, objs):
                                                           ABCSparseDataFrame))
 
 
+def _get_sliced_frame_result_type(data, obj):
+    """
+    return appropriate class of Series depending on whether
+    the data is sparse or not.
+    """
+    if is_sparse(data):
+        from pandas.core.sparse.api import SparseSeries
+        return SparseSeries
+    else:
+        return obj._constructor_sliced
+
+
 def _concat_compat(to_concat, axis=0):
     """
     provide concatenation of an array of arrays each of which is a single

pandas/core/frame.py

@@ -2562,14 +2562,8 @@ def _box_item_values(self, key, values):
 
     def _box_col_values(self, values, items):
         """ provide boxed values for a column """
-        # This check here was previously performed in Series._from_array
-        # By doing it here there is no need for that function anymore
-        # GH#19883.
-        from pandas.core.dtypes.generic import ABCSparseArray
-        this_constructor_sliced = self._constructor_sliced
-        if isinstance(values, ABCSparseArray):
-            from pandas.core.sparse.series import SparseSeries
-            this_constructor_sliced = SparseSeries
+        from pandas.core.dtypes.concat import _get_sliced_frame_result_type
+        this_constructor_sliced = _get_sliced_frame_result_type(values, self)
         return this_constructor_sliced(values, index=self.index,
                                        name=items, fastpath=True)
 

pandas/tests/frame/test_subclass.py

@@ -570,56 +570,3 @@ def strech(row):
         result = df.apply(lambda x: [1, 2, 3], axis=1)
         assert not isinstance(result, tm.SubclassedDataFrame)
         tm.assert_series_equal(result, expected)
-
-    def test_frame_subclassing_and_inherit(self):
-        # Subclass frame and series and ensure that data can be transfered
-        # between them on slicing GH#19883
-
-        class CustomSeries(Series):
-
-            def __init__(self, *args, **kw):
-                super(CustomSeries, self).__init__(*args, **kw)
-                self.extra_data = None
-
-            @property
-            def _constructor(self):
-                return CustomSeries
-
-            def __finalize__(self, other, method=None, **kwargs):
-                if method == "_inherit":
-                    self.extra_data = other.extra_data
-                return self
-
-        class CustomDataFrame(DataFrame):
-            """
-            Subclasses pandas DF, fills DF with simulation results, adds some
-            custom temporal data.
-            """
-
-            def __init__(self, *args, **kw):
-                super(CustomDataFrame, self).__init__(*args, **kw)
-                self.extra_data = None
-
-            @property
-            def _constructor(self):
-                return CustomDataFrame
-
-            @property
-            def _constructor_sliced(self):
-                def f(*args, **kwargs):
-                    return CustomSeries(*args, **kwargs).__finalize__(
-                        self, method='_inherit')
-                return f
-
-        data = {'col1': range(10),
-                'col2': range(10)}
-        cdf = CustomDataFrame(data)
-        cdf.extra_data = range(3)
-
-        # column
-        cdf_series = cdf.col1
-        assert cdf_series.extra_data == cdf.extra_data
-
-        # row
-        cdf_series = cdf.iloc[0]
-        assert cdf_series.extra_data == cdf.extra_data