add GH-number, simplify implementation

Author: topper-123

doc/source/whatsnew/v1.2.0.rst

@@ -690,7 +690,7 @@ ExtensionArray
 - Fixed bug when applying a NumPy ufunc with multiple outputs to a :class:`pandas.arrays.IntegerArray` returning None (:issue:`36913`)
 - Fixed an inconsistency in :class:`PeriodArray`'s ``__init__`` signature to those of :class:`DatetimeArray` and :class:`TimedeltaArray` (:issue:`37289`)
 - Reductions for :class:`BooleanArray`, :class:`Categorical`, :class:`DatetimeArray`, :class:`FloatingArray`, :class:`IntegerArray`, :class:`PeriodArray`, :class:`TimedeltaArray`, and :class:`PandasArray` are now keyword-only methods (:issue:`37541`)
-- Bug, where a  `ValueError` was wrongly raised if a membership check was made on an `ExtensionArray` with :class:`NA` values, but without a custom ``__contains__`` method (:issue:`xxxxx`)
+- Bug, where a  `ValueError` was wrongly raised if a membership check was made on an `ExtensionArray` with :class:`NA` values, but without a custom ``__contains__`` method (:issue:`37867`)
 
 Other
 ^^^^^

pandas/core/arrays/base.py

@@ -359,9 +359,8 @@ def __contains__(self, item) -> bool:
         # would raise a TypeError. The implementation below works around that.
         if isna(item):
             return isna(self).any() if self._can_hold_na else False
-
-        arr = self[notna(self)] if self._can_hold_na else self
-        return item in iter(arr)
+        else:
+            return (item == self).any()
 
     def __eq__(self, other: Any) -> ArrayLike:
         """

pandas/tests/arrays/categorical/test_operators.py

@@ -397,7 +397,7 @@ def test_numeric_like_ops(self):
             np.log(s)
 
     def test_contains(self, ordered):
-        # GH-xxxxx
+        # GH-37867
         cat = Categorical(["a", "b"], ordered=ordered)
         assert "a" in cat
         assert "x" not in cat

pandas/tests/arrays/string_/test_string.py

@@ -348,7 +348,7 @@ def test_astype_from_float_dtype(dtype):
 
 
 def test_contains():
-    # GH-xxxxx
+    # GH-37867
     arr = pd.arrays.StringArray(np.array(["a", "b"], dtype=object))
 
     assert "a" in arr