Consolidate some Frame APIs

python/cudf/cudf/core/_base_index.py

@@ -19,7 +19,6 @@
 from cudf._typing import DtypeObj
 from cudf.api.types import (
     is_bool_dtype,
-    is_dtype_equal,
     is_integer,
     is_integer_dtype,
     is_list_like,
@@ -34,6 +33,37 @@
     numeric_normalize_types,
 )
 
+_index_astype_docstring = """\
+Create an Index with values cast to dtypes.
+
+The class of a new Index is determined by dtype. When conversion is
+impossible, a ValueError exception is raised.
+
+Parameters
+----------
+dtype : numpy dtype
+    Use a numpy.dtype to cast entire Index object to.
+copy : bool, default False
+    By default, astype always returns a newly allocated object.
+    If copy is set to False and internal requirements on dtype are
+    satisfied, the original data is used to create a new Index
+    or the original Index is returned.
+
+Returns
+-------
+Index
+    Index with values cast to specified dtype.
+
+Examples
+--------
+>>> import cudf
+>>> index = cudf.Index([1, 2, 3])
+>>> index
+Int64Index([1, 2, 3], dtype='int64')
+>>> index.astype('float64')
+Float64Index([1.0, 2.0, 3.0], dtype='float64')
+"""
+
 
 class BaseIndex(Serializable):
     """Base class for all cudf Index types."""
@@ -1200,43 +1230,6 @@ def rename(self, name, inplace=False):
             out.name = name
             return out
 
-    def astype(self, dtype, copy=False):
-        """
-        Create an Index with values cast to dtypes. The class of a new Index
-        is determined by dtype. When conversion is impossible, a ValueError
-        exception is raised.
-
-        Parameters
-        ----------
-        dtype : numpy dtype
-            Use a numpy.dtype to cast entire Index object to.
-        copy : bool, default False
-            By default, astype always returns a newly allocated object.
-            If copy is set to False and internal requirements on dtype are
-            satisfied, the original data is used to create a new Index
-            or the original Index is returned.
-
-        Returns
-        -------
-        Index
-            Index with values cast to specified dtype.
-
-        Examples
-        --------
-        >>> import cudf
-        >>> index = cudf.Index([1, 2, 3])
-        >>> index
-        Int64Index([1, 2, 3], dtype='int64')
-        >>> index.astype('float64')
-        Float64Index([1.0, 2.0, 3.0], dtype='float64')
-        """
-        if is_dtype_equal(dtype, self.dtype):
-            return self.copy(deep=copy)
-
-        return cudf.Index(
-            self.copy(deep=copy)._values.astype(dtype), name=self.name
-        )
-
     def to_series(self, index=None, name=None):
         """
         Create a Series with both index and values equal to the index keys.
@@ -1278,7 +1271,7 @@ def get_slice_bound(self, label, side, kind=None):
         int
             Index of label.
         """
-        raise (NotImplementedError)
+        raise NotImplementedError
 
     def __array_function__(self, func, types, args, kwargs):