DEPR: deprecate get_ftype_counts (GH18243)

Deprecate NDFrame.get_ftype_counts()

Author: GGordonGordon

doc/source/whatsnew/v0.23.0.txt

@@ -740,6 +740,7 @@ Deprecations
 
 - ``pandas.tseries.plotting.tsplot`` is deprecated. Use :func:`Series.plot` instead (:issue:`18627`)
 - ``Index.summary()`` is deprecated and will be removed in a future version (:issue:`18217`)
+- ``NDFrame.get_ftype_counts()`` is deprecated and will be removed in a future version (:issue:`18243`)
 
 .. _whatsnew_0230.prior_deprecations:
 

pandas/core/generic.py

@@ -4677,6 +4677,8 @@ def get_ftype_counts(self):
         """
         Return counts of unique ftypes in this object.
 
+        .. deprecated:: 0.23.0
+
         This is useful for SparseDataFrame or for DataFrames containing
         sparse arrays.
 
@@ -4707,6 +4709,45 @@ def get_ftype_counts(self):
         object:dense     1
         dtype: int64
         """
+        warnings.warn("get_ftype_counts is deprecated and will "
+                      "be removed in a future version",
+                      FutureWarning, stacklevel=2)
+        return self._get_ftype_counts()
+
+    def _get_ftype_counts(self):
+        """
+        Return counts of unique ftypes in this object.
+
+        This is useful for SparseDataFrame or for DataFrames containing
+        sparse arrays.
+
+        Returns
+        -------
+        dtype : Series
+            Series with the count of columns with each type and
+            sparsity (dense/sparse)
+
+        See Also
+        --------
+        ftypes : Return ftypes (indication of sparse/dense and dtype) in
+            this object.
+
+        Examples
+        --------
+        >>> a = [['a', 1, 1.0], ['b', 2, 2.0], ['c', 3, 3.0]]
+        >>> df = pd.DataFrame(a, columns=['str', 'int', 'float'])
+        >>> df
+          str  int  float
+        0   a    1    1.0
+        1   b    2    2.0
+        2   c    3    3.0
+
+        >>> df._get_ftype_counts()
+        float64:dense    1
+        int64:dense      1
+        object:dense     1
+        dtype: int64
+        """
         from pandas import Series
         return Series(self._data.get_ftype_counts())
 

pandas/tests/generic/test_generic.py

@@ -1008,3 +1008,11 @@ def test_pipe_panel(self):
 
             with pytest.raises(ValueError):
                 result = wp.pipe((f, 'y'), x=1, y=1)
+
+    # GH18243
+    def test_get_ftype_counts_deprecated(self):
+        a = [['a', 1, 1.0], ['b', 2, 2.0], ['c', 3, 3.0]]
+        df = DataFrame(a, columns=['str', 'int', 'float'])
+
+        with tm.assert_produces_warning(FutureWarning):
+            df.get_ftype_counts()

pandas/tests/series/test_dtypes.py

@@ -64,7 +64,7 @@ def test_dtype(self):
         assert self.ts.ftypes == 'float64:dense'
         tm.assert_series_equal(self.ts.get_dtype_counts(),
                                Series(1, ['float64']))
-        tm.assert_series_equal(self.ts.get_ftype_counts(),
+        tm.assert_series_equal(self.ts._get_ftype_counts(),
                                Series(1, ['float64:dense']))
 
     @pytest.mark.parametrize("value", [np.nan, np.inf])