REF: make Series._replace_single a regular method (#37691)

Author: jbrockmendel

pandas/core/generic.py

@@ -137,36 +137,6 @@
 )
 
 
-def _single_replace(self: "Series", to_replace, method, inplace, limit):
-    """
-    Replaces values in a Series using the fill method specified when no
-    replacement value is given in the replace method
-    """
-    if self.ndim != 1:
-        raise TypeError(
-            f"cannot replace {to_replace} with method {method} on a "
-            f"{type(self).__name__}"
-        )
-
-    orig_dtype = self.dtype
-    result = self if inplace else self.copy()
-    fill_f = missing.get_fill_func(method)
-
-    mask = missing.mask_missing(result.values, to_replace)
-    values = fill_f(result.values, limit=limit, mask=mask)
-
-    if values.dtype == orig_dtype and inplace:
-        return
-
-    result = pd.Series(values, index=self.index, dtype=self.dtype).__finalize__(self)
-
-    if inplace:
-        self._update_inplace(result)
-        return
-
-    return result
-
-
 bool_t = bool  # Need alias because NDFrame has def bool:
 
 
@@ -6690,11 +6660,14 @@ def replace(
 
             if isinstance(to_replace, (tuple, list)):
                 if isinstance(self, ABCDataFrame):
+                    from pandas import Series
+
                     return self.apply(
-                        _single_replace, args=(to_replace, method, inplace, limit)
+                        Series._replace_single,
+                        args=(to_replace, method, inplace, limit),
                     )
                 self = cast("Series", self)
-                return _single_replace(self, to_replace, method, inplace, limit)
+                return self._replace_single(to_replace, method, inplace, limit)
 
             if not is_dict_like(to_replace):
                 if not is_dict_like(regex):

pandas/core/series.py

@@ -67,7 +67,7 @@
     remove_na_arraylike,
 )
 
-from pandas.core import algorithms, base, generic, nanops, ops
+from pandas.core import algorithms, base, generic, missing, nanops, ops
 from pandas.core.accessor import CachedAccessor
 from pandas.core.aggregation import aggregate, transform
 from pandas.core.arrays import ExtensionArray
@@ -4558,6 +4558,31 @@ def replace(
             method=method,
         )
 
+    def _replace_single(self, to_replace, method, inplace, limit):
+        """
+        Replaces values in a Series using the fill method specified when no
+        replacement value is given in the replace method
+        """
+
+        orig_dtype = self.dtype
+        result = self if inplace else self.copy()
+        fill_f = missing.get_fill_func(method)
+
+        mask = missing.mask_missing(result.values, to_replace)
+        values = fill_f(result.values, limit=limit, mask=mask)
+
+        if values.dtype == orig_dtype and inplace:
+            return
+
+        result = self._constructor(values, index=self.index, dtype=self.dtype)
+        result = result.__finalize__(self)
+
+        if inplace:
+            self._update_inplace(result)
+            return
+
+        return result
+
     @doc(NDFrame.shift, klass=_shared_doc_kwargs["klass"])
     def shift(self, periods=1, freq=None, axis=0, fill_value=None) -> "Series":
         return super().shift(