DEPR: deprecate (Sparse)Series.from_array (#18258)

Author: jorisvandenbossche

doc/source/whatsnew/v0.22.0.txt

@@ -54,7 +54,7 @@ Other API Changes
 Deprecations
 ~~~~~~~~~~~~
 
--
+- ``Series.from_array`` and ``SparseSeries.from_array`` are deprecated. Use the normal constructor ``Series(..)`` and ``SparseSeries(..)`` instead (:issue:`18213`).
 -
 -
 

pandas/core/frame.py

@@ -2099,10 +2099,8 @@ def _ixs(self, i, axis=0):
 
                 if index_len and not len(values):
                     values = np.array([np.nan] * index_len, dtype=object)
-                result = self._constructor_sliced.from_array(values,
-                                                             index=self.index,
-                                                             name=label,
-                                                             fastpath=True)
+                result = self._constructor_sliced._from_array(
+                    values, index=self.index, name=label, fastpath=True)
 
                 # this is a cached value, mark it so
                 result._set_as_cached(label, self)
@@ -2497,8 +2495,8 @@ def _box_item_values(self, key, values):
 
     def _box_col_values(self, values, items):
         """ provide boxed values for a column """
-        return self._constructor_sliced.from_array(values, index=self.index,
-                                                   name=items, fastpath=True)
+        return self._constructor_sliced._from_array(values, index=self.index,
+                                                    name=items, fastpath=True)
 
     def __setitem__(self, key, value):
         key = com._apply_if_callable(key, self)
@@ -4939,8 +4937,8 @@ def _apply_standard(self, func, axis, ignore_failures=False, reduce=True):
             res_index = self.index
             res_columns = self.columns
             values = self.values
-            series_gen = (Series.from_array(arr, index=res_columns, name=name,
-                                            dtype=dtype)
+            series_gen = (Series._from_array(arr, index=res_columns, name=name,
+                                             dtype=dtype)
                           for i, (arr, name) in enumerate(zip(values,
                                                               res_index)))
         else:  # pragma : no cover

pandas/core/series.py

@@ -273,6 +273,25 @@ def __init__(self, data=None, index=None, dtype=None, name=None,
     @classmethod
     def from_array(cls, arr, index=None, name=None, dtype=None, copy=False,
                    fastpath=False):
+        """
+        DEPRECATED: use the pd.Series(..) constructor instead.
+
+        """
+        warnings.warn("'from_array' is deprecated and will be removed in a "
+                      "future version. Please use the pd.Series(..) "
+                      "constructor instead.", FutureWarning, stacklevel=2)
+        return cls._from_array(arr, index=index, name=name, dtype=dtype,
+                               copy=copy, fastpath=fastpath)
+
+    @classmethod
+    def _from_array(cls, arr, index=None, name=None, dtype=None, copy=False,
+                    fastpath=False):
+        """
+        Internal method used in DataFrame.__setitem__/__getitem__.
+        Difference with Series(..) is that this method checks if a sparse
+        array is passed.
+
+        """
         # return a sparse series here
         if isinstance(arr, ABCSparseArray):
             from pandas.core.sparse.series import SparseSeries

pandas/core/sparse/series.py

@@ -256,8 +256,18 @@ def npoints(self):
     def from_array(cls, arr, index=None, name=None, copy=False,
                    fill_value=None, fastpath=False):
         """
-        Simplified alternate constructor
+        DEPRECATED: use the pd.SparseSeries(..) constructor instead.
+
         """
+        warnings.warn("'from_array' is deprecated and will be removed in a "
+                      "future version. Please use the pd.SparseSeries(..) "
+                      "constructor instead.", FutureWarning, stacklevel=2)
+        return cls._from_array(arr, index=index, name=name, copy=copy,
+                               fill_value=fill_value, fastpath=fastpath)
+
+    @classmethod
+    def _from_array(cls, arr, index=None, name=None, copy=False,
+                    fill_value=None, fastpath=False):
         return cls(arr, index=index, name=name, copy=copy,
                    fill_value=fill_value, fastpath=fastpath)
 

pandas/tests/series/test_api.py

@@ -195,6 +195,11 @@ def test_constructor_dict_timedelta_index(self):
         )
         self._assert_series_equal(result, expected)
 
+    def test_from_array_deprecated(self):
+
+        with tm.assert_produces_warning(FutureWarning):
+            self.series_klass.from_array([1, 2, 3])
+
 
 class TestSeriesMisc(TestData, SharedWithSparse):
 

pandas/tests/series/test_timeseries.py

@@ -935,8 +935,9 @@ def test_from_M8_structured(self):
         assert isinstance(s[0], Timestamp)
         assert s[0] == dates[0][0]
 
-        s = Series.from_array(arr['Date'], Index([0]))
-        assert s[0] == dates[0][0]
+        with pytest.warns(FutureWarning):
+            s = Series.from_array(arr['Date'], Index([0]))
+            assert s[0] == dates[0][0]
 
     def test_get_level_values_box(self):
         from pandas import MultiIndex