API/CLN: simplify CategoricalBlock.replace (#33279)

Author: jbrockmendel

pandas/core/internals/blocks.py

@@ -2753,18 +2753,9 @@ def replace(
     ):
         inplace = validate_bool_kwarg(inplace, "inplace")
         result = self if inplace else self.copy()
-        if filter is None:  # replace was called on a series
-            result.values.replace(to_replace, value, inplace=True)
-            if convert:
-                return result.convert(numeric=False, copy=not inplace)
-            else:
-                return result
-        else:  # replace was called on a DataFrame
-            if not isna(value):
-                result.values.add_categories(value, inplace=True)
-            return super(CategoricalBlock, result).replace(
-                to_replace, value, inplace, filter, regex, convert
-            )
+
+        result.values.replace(to_replace, value, inplace=True)
+        return result
 
 
 # -----------------------------------------------------------------

pandas/tests/frame/methods/test_replace.py

@@ -1303,9 +1303,15 @@ def test_replace_method(self, to_replace, method, expected):
     def test_categorical_replace_with_dict(self, replace_dict, final_data):
         # GH 26988
         df = DataFrame([[1, 1], [2, 2]], columns=["a", "b"], dtype="category")
-        expected = DataFrame(final_data, columns=["a", "b"], dtype="category")
-        expected["a"] = expected["a"].cat.set_categories([1, 2, 3])
-        expected["b"] = expected["b"].cat.set_categories([1, 2, 3])
+
+        final_data = np.array(final_data)
+
+        a = pd.Categorical(final_data[:, 0], categories=[3, 2])
+
+        excat = [3, 2] if replace_dict["b"] == 1 else [1, 3]
+        b = pd.Categorical(final_data[:, 1], categories=excat)
+
+        expected = DataFrame({"a": a, "b": b})
         result = df.replace(replace_dict, 3)
         tm.assert_frame_equal(result, expected)
         with pytest.raises(AssertionError):