DEPR: deprecate get_ftype_counts (GH18243) (pandas-dev#20404)

Author: GGordonGordon

doc/source/whatsnew/v0.23.0.txt

@@ -744,6 +744,7 @@ 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

@@ -4726,6 +4726,8 @@ 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.
 
@@ -4756,6 +4758,10 @@ 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)
+
         from pandas import Series
         return Series(self._data.get_ftype_counts())
 

pandas/tests/series/test_dtypes.py

@@ -64,8 +64,10 @@ 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(),
-                               Series(1, ['float64:dense']))
+        # GH18243 - Assert .get_ftype_counts is deprecated
+        with tm.assert_produces_warning(FutureWarning):
+            tm.assert_series_equal(self.ts.get_ftype_counts(),
+                                   Series(1, ['float64:dense']))
 
     @pytest.mark.parametrize("value", [np.nan, np.inf])
     @pytest.mark.parametrize("dtype", [np.int32, np.int64])