REF: consolidate NDFrame._iset_item, _set_item with DataFrame methods (pandas-dev#38389)

Author: jbrockmendel

pandas/core/frame.py

@@ -3211,12 +3211,16 @@ def _setitem_frame(self, key, value):
         self._check_setitem_copy()
         self._where(-key, value, inplace=True)
 
-    def _iset_item(self, loc: int, value):
+    def _iset_item_mgr(self, loc: int, value) -> None:
+        self._mgr.iset(loc, value)
+        self._clear_item_cache()
+
+    def _iset_item(self, loc: int, value, broadcast: bool = False):
 
         # technically _sanitize_column expects a label, not a position,
         #  but the behavior is the same as long as we pass broadcast=False
-        value = self._sanitize_column(loc, value, broadcast=False)
-        NDFrame._iset_item(self, loc, value)
+        value = self._sanitize_column(loc, value, broadcast=broadcast)
+        self._iset_item_mgr(loc, value)
 
         # check if we are modifying a copy
         # try to set first as we want an invalid
@@ -3235,7 +3239,14 @@ def _set_item(self, key, value):
         ensure homogeneity.
         """
         value = self._sanitize_column(key, value)
-        NDFrame._set_item(self, key, value)
+
+        try:
+            loc = self._info_axis.get_loc(key)
+        except KeyError:
+            # This item wasn't present, just insert at end
+            self._mgr.insert(len(self._info_axis), key, value)
+        else:
+            self._iset_item_mgr(loc, value)
 
         # check if we are modifying a copy
         # try to set first as we want an invalid

pandas/core/generic.py

@@ -3814,20 +3814,6 @@ def _slice(self: FrameOrSeries, slobj: slice, axis=0) -> FrameOrSeries:
         result._set_is_copy(self, copy=is_copy)
         return result
 
-    def _iset_item(self, loc: int, value) -> None:
-        self._mgr.iset(loc, value)
-        self._clear_item_cache()
-
-    def _set_item(self, key, value) -> None:
-        try:
-            loc = self._info_axis.get_loc(key)
-        except KeyError:
-            # This item wasn't present, just insert at end
-            self._mgr.insert(len(self._info_axis), key, value)
-            return
-
-        NDFrame._iset_item(self, loc, value)
-
     @final
     def _set_is_copy(self, ref, copy: bool_t = True) -> None:
         if not copy: