REF: use only inherit_names in CategoricalIndex (pandas-dev#42100)

Author: jbrockmendel

pandas/core/indexes/category.py

@@ -27,7 +27,6 @@
     notna,
 )
 
-from pandas.core import accessor
 from pandas.core.arrays.categorical import (
     Categorical,
     contains,
@@ -63,9 +62,8 @@
     ],
     Categorical,
 )
-@accessor.delegate_names(
-    delegate=Categorical,
-    accessors=[
+@inherit_names(
+    [
         "rename_categories",
         "reorder_categories",
         "add_categories",
@@ -75,10 +73,10 @@
         "as_ordered",
         "as_unordered",
     ],
-    typ="method",
-    overwrite=True,
+    Categorical,
+    wrap=True,
 )
-class CategoricalIndex(NDArrayBackedExtensionIndex, accessor.PandasDelegate):
+class CategoricalIndex(NDArrayBackedExtensionIndex):
     """
     Index based on an underlying :class:`Categorical`.
 
@@ -562,13 +560,3 @@ def _concat(self, to_concat: list[Index], name: Hashable) -> Index:
         else:
             cat = self._data._from_backing_data(codes)
             return type(self)._simple_new(cat, name=name)
-
-    def _delegate_method(self, name: str, *args, **kwargs):
-        """method delegation to the ._values"""
-        method = getattr(self._values, name)
-        if "inplace" in kwargs:
-            raise ValueError("cannot use inplace with CategoricalIndex")
-        res = method(*args, **kwargs)
-        if is_scalar(res):
-            return res
-        return CategoricalIndex(res, name=self.name)

pandas/core/indexes/extension.py

@@ -102,6 +102,8 @@ def fset(self, value):
     else:
 
         def method(self, *args, **kwargs):
+            if "inplace" in kwargs:
+                raise ValueError(f"cannot use inplace with {type(self).__name__}")
             result = attr(self._data, *args, **kwargs)
             if wrap:
                 if isinstance(result, type(self._data)):