REF: move Loc method that belongs on Index

pandas/core/indexes/base.py

@@ -3101,6 +3101,16 @@ def _filter_indexer_tolerance(
     # --------------------------------------------------------------------
     # Indexer Conversion Methods
 
+    def _get_partial_string_timestamp_match_key(self, key):
+        """
+        Translate any partial string timestamp matches in key, returning the
+        new key.
+
+        Only relevant for MultiIndex.
+        """
+        # GH#10331
+        return key
+
     def _convert_scalar_indexer(self, key, kind: str_t):
         """
         Convert a scalar indexer.

pandas/core/indexes/multi.py

@@ -2396,6 +2396,35 @@ def _convert_listlike_indexer(self, keyarr):
 
         return indexer, keyarr
 
+    def _get_partial_string_timestamp_match_key(self, key):
+        """
+        Translate any partial string timestamp matches in key, returning the
+        new key.
+
+        Only relevant for MultiIndex.
+        """
+        # GH#10331
+        if isinstance(key, str) and self.levels[0]._supports_partial_string_indexing:
+            # Convert key '2016-01-01' to
+            # ('2016-01-01'[, slice(None, None, None)]+)
+            key = tuple([key] + [slice(None)] * (len(self.levels) - 1))
+
+        if isinstance(key, tuple):
+            # Convert (..., '2016-01-01', ...) in tuple to
+            # (..., slice('2016-01-01', '2016-01-01', None), ...)
+            new_key = []
+            for i, component in enumerate(key):
+                if (
+                    isinstance(component, str)
+                    and self.levels[i]._supports_partial_string_indexing
+                ):
+                    new_key.append(slice(component, component, None))
+                else:
+                    new_key.append(component)
+            key = tuple(new_key)
+
+        return key
+
     @Appender(_index_shared_docs["get_indexer"] % _index_doc_kwargs)
     def get_indexer(self, target, method=None, limit=None, tolerance=None):
         method = missing.clean_reindex_fill_method(method)

pandas/core/indexing.py

@@ -980,38 +980,6 @@ def _multi_take(self, tup: Tuple):
 
     # -------------------------------------------------------------------
 
-    def _get_partial_string_timestamp_match_key(self, key, labels):
-        """
-        Translate any partial string timestamp matches in key, returning the
-        new key.
-
-        (GH 10331)
-        """
-        if isinstance(labels, ABCMultiIndex):
-            if (
-                isinstance(key, str)
-                and labels.levels[0]._supports_partial_string_indexing
-            ):
-                # Convert key '2016-01-01' to
-                # ('2016-01-01'[, slice(None, None, None)]+)
-                key = tuple([key] + [slice(None)] * (len(labels.levels) - 1))
-
-            if isinstance(key, tuple):
-                # Convert (..., '2016-01-01', ...) in tuple to
-                # (..., slice('2016-01-01', '2016-01-01', None), ...)
-                new_key = []
-                for i, component in enumerate(key):
-                    if (
-                        isinstance(component, str)
-                        and labels.levels[i]._supports_partial_string_indexing
-                    ):
-                        new_key.append(slice(component, component, None))
-                    else:
-                        new_key.append(component)
-                key = tuple(new_key)
-
-        return key
-
     def _getitem_iterable(self, key, axis: int):
         """
         Index current object with an an iterable collection of keys.
@@ -1072,7 +1040,7 @@ def _getitem_axis(self, key, axis: int):
             key = list(key)
 
         labels = self.obj._get_axis(axis)
-        key = self._get_partial_string_timestamp_match_key(key, labels)
+        key = labels._get_partial_string_timestamp_match_key(key)
 
         if isinstance(key, slice):
             self._validate_key(key, axis)