refactor, use _can_hold_strings

Author: topper-123

pandas/core/indexes/base.py

@@ -231,6 +231,7 @@ def _outer_indexer(self, left, right):
     _attributes = ["name"]
     _is_numeric_dtype = False
     _can_hold_na = True
+    _can_hold_strings = True
 
     # would we like our indexing holder to defer to us
     _defer_to_indexing = False
@@ -572,14 +573,18 @@ def _engine(self):
     @cache_readonly
     def _dir_additions_for_owner(self) -> Set[str_t]:
         """
-        Add the string-like attributes from this index to the owners' dir output.
+        Add the string-like labels to the owner dataframe/series dir output.
+
         If this is a MultiIndex, it's first level values are used.
         """
-        return {
-            c
-            for c in self.unique(level=0)[:100]
-            if isinstance(c, str) and c.isidentifier()
-        }
+        if self._can_hold_strings:
+            return {
+                c
+                for c in self.unique(level=0)[:100]
+                if isinstance(c, str) and c.isidentifier()
+            }
+        else:
+            return set()
 
     # --------------------------------------------------------------------
     # Array-Like Methods

pandas/core/indexes/datetimelike.py

@@ -2,7 +2,7 @@
 Base and utility classes for tseries type pandas objects.
 """
 from datetime import datetime, tzinfo
-from typing import TYPE_CHECKING, Any, List, Optional, Set, TypeVar, Union, cast
+from typing import TYPE_CHECKING, Any, List, Optional, TypeVar, Union, cast
 
 import numpy as np
 
@@ -88,6 +88,7 @@ class DatetimeIndexOpsMixin(ExtensionIndex):
     Common ops mixin to support a unified interface datetimelike Index.
     """
 
+    _can_hold_strings = False
     _data: Union[DatetimeArray, TimedeltaArray, PeriodArray]
     freq: Optional[BaseOffset]
     freqstr: Optional[str]
@@ -105,10 +106,6 @@ class DatetimeIndexOpsMixin(ExtensionIndex):
     def _is_all_dates(self) -> bool:
         return True
 
-    @cache_readonly
-    def _dir_additions_for_owner(self) -> Set[str]:
-        return set()
-
     # ------------------------------------------------------------------------
     # Abstract data attributes
 

pandas/core/indexes/interval.py

@@ -2,7 +2,7 @@
 from functools import wraps
 from operator import le, lt
 import textwrap
-from typing import TYPE_CHECKING, Any, List, Optional, Set, Tuple, Union, cast
+from typing import TYPE_CHECKING, Any, List, Optional, Tuple, Union, cast
 
 import numpy as np
 
@@ -193,6 +193,7 @@ class IntervalIndex(IntervalMixin, ExtensionIndex):
 
     _data: IntervalArray
     _values: IntervalArray
+    _can_hold_strings = True
 
     # --------------------------------------------------------------------
     # Constructors
@@ -371,10 +372,6 @@ def __contains__(self, key: Any) -> bool:
     def _multiindex(self) -> MultiIndex:
         return MultiIndex.from_arrays([self.left, self.right], names=["left", "right"])
 
-    @cache_readonly
-    def _dir_additions_for_owner(self) -> Set[str]:
-        return set()
-
     @cache_readonly
     def values(self) -> IntervalArray:
         """

pandas/core/indexes/numeric.py

@@ -1,4 +1,4 @@
-from typing import Any, Set
+from typing import Any
 
 import numpy as np
 
@@ -42,6 +42,7 @@ class NumericIndex(Index):
     _default_dtype: np.dtype
 
     _is_numeric_dtype = True
+    _can_hold_strings = False
 
     def __new__(cls, data=None, dtype=None, copy=False, name=None):
         cls._validate_dtype(dtype)
@@ -184,10 +185,6 @@ def _union(self, other, sort):
         else:
             return super()._union(other, sort)
 
-    @cache_readonly
-    def _dir_additions_for_owner(self) -> Set[str]:
-        return set()
-
 
 _num_index_shared_docs[
     "class_descr"