DEPR: index argument to SparseArray (#43523)

doc/source/whatsnew/v1.4.0.rst

@@ -282,6 +282,8 @@ Other Deprecations
 - Deprecated passing in a string column label into ``times`` in :meth:`DataFrame.ewm` (:issue:`43265`)
 - Deprecated the 'include_start' and 'include_end' arguments in :meth:`DataFrame.between_time`; in a future version passing 'include_start' or 'include_end' will raise (:issue:`40245`)
 - Deprecated the ``squeeze`` argument to :meth:`read_csv`, :meth:`read_table`, and :meth:`read_excel`. Users should squeeze the DataFrame afterwards with ``.squeeze("columns")`` instead. (:issue:`43242`)
+- Deprecated the ``index`` argument to :class:`SparseArray` construction (:issue:`23089`)
+-
 
 .. ---------------------------------------------------------------------------
 

pandas/core/arrays/sparse/array.py

@@ -41,6 +41,7 @@
 )
 from pandas.compat.numpy import function as nv
 from pandas.errors import PerformanceWarning
+from pandas.util._exceptions import find_stack_level
 
 from pandas.core.dtypes.cast import (
     astype_nansafe,
@@ -258,6 +259,11 @@ class SparseArray(OpsMixin, PandasObject, ExtensionArray):
         `fill_value`.
     sparse_index : SparseIndex, optional
     index : Index
+
+        .. deprecated:: 1.4.0
+            Use a function like `np.full` to construct an array with the desired
+            repeats of the scalar value instead.
+
     fill_value : scalar, optional
         Elements in `data` that are `fill_value` are not stored in the
         SparseArray. For memory savings, this should be the most common value
@@ -361,6 +367,16 @@ def __init__(
                 fill_value = dtype.fill_value
             dtype = dtype.subtype
 
+        if index is not None:
+            warnings.warn(
+                "The index argument has been deprecated and will be "
+                "removed in a future version. Use a function like np.full "
+                "to construct an array with the desired repeats of the "
+                "scalar value instead.\n\n",
+                FutureWarning,
+                stacklevel=find_stack_level(),
+            )
+
         if index is not None and not is_scalar(data):
             raise Exception("must only pass scalars with an index")
 

pandas/tests/arrays/sparse/test_array.py

@@ -237,7 +237,10 @@ def test_from_spmatrix_raises(self):
     )
     def test_scalar_with_index_infer_dtype(self, scalar, dtype):
         # GH 19163
-        arr = SparseArray(scalar, index=[1, 2, 3], fill_value=scalar)
+        with tm.assert_produces_warning(
+            FutureWarning, match="The index argument has been deprecated"
+        ):
+            arr = SparseArray(scalar, index=[1, 2, 3], fill_value=scalar)
         exp = SparseArray([scalar, scalar, scalar], fill_value=scalar)
 
         tm.assert_sp_array_equal(arr, exp)