Added condition for CategoricalDtype

Author: arthurlw

pandas/core/arrays/base.py

@@ -757,13 +757,20 @@ def astype(self, dtype: AstypeArg, copy: bool = True) -> ArrayLike:
         >>> arr2.dtype
         dtype('float64')
         """
+        from pandas.api.types import CategoricalDtype
+
         dtype = pandas_dtype(dtype)
         if dtype == self.dtype:
             if not copy:
                 return self
             else:
                 return self.copy()
 
+        if isinstance(dtype, CategoricalDtype):
+            from pandas.core.arrays import Categorical
+
+            return Categorical(self.to_numpy(), dtype=dtype)
+
         if isinstance(dtype, ExtensionDtype):
             cls = dtype.construct_array_type()
             return cls._from_sequence(self, dtype=dtype, copy=copy)