PERF: BaseMaskedArray._empty (#53040)

* PERF: BaseMaskedArray._empty

* update

* use .fill method

Author: topper-123

pandas/core/arrays/masked.py

@@ -131,6 +131,19 @@ def _from_sequence(cls, scalars, *, dtype=None, copy: bool = False) -> Self:
         values, mask = cls._coerce_to_array(scalars, dtype=dtype, copy=copy)
         return cls(values, mask)
 
+    @classmethod
+    @doc(ExtensionArray._empty)
+    def _empty(cls, shape: Shape, dtype: ExtensionDtype):
+        values = np.empty(shape, dtype=dtype.type)
+        values.fill(cls._internal_fill_value)
+        mask = np.ones(shape, dtype=bool)
+        result = cls(values, mask)
+        if not isinstance(result, cls) or dtype != result.dtype:
+            raise NotImplementedError(
+                f"Default 'empty' implementation is invalid for dtype='{dtype}'"
+            )
+        return result
+
     @property
     def dtype(self) -> BaseMaskedDtype:
         raise AbstractMethodError(self)

pandas/core/dtypes/base.py

@@ -211,7 +211,7 @@ def construct_array_type(cls) -> type_t[ExtensionArray]:
         """
         raise AbstractMethodError(cls)
 
-    def empty(self, shape: Shape) -> type_t[ExtensionArray]:
+    def empty(self, shape: Shape) -> ExtensionArray:
         """
         Construct an ExtensionArray of this dtype with the given shape.