REF: Dispatch string methods to ExtensionArray

ci/code_checks.sh

@@ -335,7 +335,7 @@ if [[ -z "$CHECK" || "$CHECK" == "doctests" ]]; then
     RET=$(($RET + $?)) ; echo $MSG "DONE"
 
     MSG='Doctests strings.py' ; echo $MSG
-    pytest -q --doctest-modules pandas/core/strings.py
+    pytest -q --doctest-modules pandas/core/strings/
     RET=$(($RET + $?)) ; echo $MSG "DONE"
 
     # Directories

pandas/core/arrays/categorical.py

@@ -41,7 +41,7 @@
 from pandas.core.dtypes.missing import is_valid_nat_for_dtype, isna, notna
 
 from pandas.core import ops
-from pandas.core.accessor import PandasDelegate, delegate_names
+from pandas.core.accessor import CachedAccessor, PandasDelegate, delegate_names
 import pandas.core.algorithms as algorithms
 from pandas.core.algorithms import factorize, get_data_algo, take_1d, unique1d
 from pandas.core.arrays._mixins import NDArrayBackedExtensionArray
@@ -52,6 +52,7 @@
 from pandas.core.missing import interpolate_2d
 from pandas.core.ops.common import unpack_zerodim_and_defer
 from pandas.core.sorting import nargsort
+from pandas.core.strings.categorical import CategoricalStringMethods
 
 from pandas.io.formats import console
 
@@ -2336,6 +2337,8 @@ def replace(self, to_replace, value, inplace: bool = False):
         if not inplace:
             return cat
 
+    _str = CachedAccessor("_str", CategoricalStringMethods)
+
 
 # The Series.cat accessor
 

pandas/core/arrays/string_.py

@@ -6,16 +6,17 @@
 from pandas._libs import lib, missing as libmissing
 
 from pandas.core.dtypes.base import ExtensionDtype, register_extension_dtype
-from pandas.core.dtypes.common import pandas_dtype
-from pandas.core.dtypes.inference import is_array_like
+from pandas.core.dtypes.common import is_array_like, pandas_dtype
 
 from pandas import compat
 from pandas.core import ops
+from pandas.core.accessor import CachedAccessor
 from pandas.core.arrays import IntegerArray, PandasArray
 from pandas.core.arrays.integer import _IntegerDtype
 from pandas.core.construction import extract_array
 from pandas.core.indexers import check_array_indexer
 from pandas.core.missing import isna
+from pandas.core.strings.string_array import StringArrayMethods
 
 if TYPE_CHECKING:
     import pyarrow  # noqa: F401
@@ -343,6 +344,7 @@ def _add_arithmetic_ops(cls):
         cls.__rmul__ = cls._create_arithmetic_method(ops.rmul)
 
     _create_comparison_method = _create_arithmetic_method
+    _str = CachedAccessor("_str", StringArrayMethods)
 
 
 StringArray._add_arithmetic_ops()