REF: make _convert_scalar_indexer require a scalar (#31676)

Author: jbrockmendel

pandas/core/indexes/datetimelike.py

@@ -398,15 +398,17 @@ def _convert_scalar_indexer(self, key, kind=None):
 
         assert kind in ["loc", "getitem", "iloc", None]
 
+        if not is_scalar(key):
+            raise TypeError(key)
+
         # we don't allow integer/float indexing for loc
-        # we don't allow float indexing for ix/getitem
-        if is_scalar(key):
-            is_int = is_integer(key)
-            is_flt = is_float(key)
-            if kind in ["loc"] and (is_int or is_flt):
-                self._invalid_indexer("index", key)
-            elif kind in ["getitem"] and is_flt:
-                self._invalid_indexer("index", key)
+        # we don't allow float indexing for getitem
+        is_int = is_integer(key)
+        is_flt = is_float(key)
+        if kind == "loc" and (is_int or is_flt):
+            self._invalid_indexer("index", key)
+        elif kind == "getitem" and is_flt:
+            self._invalid_indexer("index", key)
 
         return super()._convert_scalar_indexer(key, kind=kind)
 

pandas/core/indexing.py

@@ -599,7 +599,7 @@ def _slice(self, obj, axis: int, kind=None):
 
     def _get_setitem_indexer(self, key):
         if self.axis is not None:
-            return self._convert_tuple(key)
+            return self._convert_tuple(key, setting=True)
 
         ax = self.obj._get_axis(0)
 
@@ -612,15 +612,15 @@ def _get_setitem_indexer(self, key):
 
         if isinstance(key, tuple):
             try:
-                return self._convert_tuple(key)
+                return self._convert_tuple(key, setting=True)
             except IndexingError:
                 pass
 
         if isinstance(key, range):
             return list(key)
 
         try:
-            return self._convert_to_indexer(key, axis=0)
+            return self._convert_to_indexer(key, axis=0, setting=True)
         except TypeError as e:
 
             # invalid indexer type vs 'other' indexing errors
@@ -683,20 +683,22 @@ def _is_nested_tuple_indexer(self, tup: Tuple) -> bool:
             return any(is_nested_tuple(tup, ax) for ax in self.obj.axes)
         return False
 
-    def _convert_tuple(self, key):
+    def _convert_tuple(self, key, setting: bool = False):
         keyidx = []
         if self.axis is not None:
             axis = self.obj._get_axis_number(self.axis)
             for i in range(self.ndim):
                 if i == axis:
-                    keyidx.append(self._convert_to_indexer(key, axis=axis))
+                    keyidx.append(
+                        self._convert_to_indexer(key, axis=axis, setting=setting)
+                    )
                 else:
                     keyidx.append(slice(None))
         else:
             for i, k in enumerate(key):
                 if i >= self.ndim:
                     raise IndexingError("Too many indexers")
-                idx = self._convert_to_indexer(k, axis=i)
+                idx = self._convert_to_indexer(k, axis=i, setting=setting)
                 keyidx.append(idx)
         return tuple(keyidx)
 
@@ -1566,7 +1568,7 @@ def _validate_read_indexer(
                     "https://pandas.pydata.org/pandas-docs/stable/user_guide/indexing.html#deprecate-loc-reindex-listlike"  # noqa:E501
                 )
 
-    def _convert_to_indexer(self, key, axis: int):
+    def _convert_to_indexer(self, key, axis: int, setting: bool = False):
         raise AbstractMethodError(self)
 
     def __getitem__(self, key):
@@ -1775,7 +1777,7 @@ def _get_slice_axis(self, slice_obj: slice, axis: int):
             #  return a DatetimeIndex instead of a slice object.
             return self.obj.take(indexer, axis=axis)
 
-    def _convert_to_indexer(self, key, axis: int):
+    def _convert_to_indexer(self, key, axis: int, setting: bool = False):
         """
         Convert indexing key into something we can use to do actual fancy
         indexing on a ndarray.
@@ -1795,12 +1797,14 @@ def _convert_to_indexer(self, key, axis: int):
         if isinstance(key, slice):
             return self._convert_slice_indexer(key, axis)
 
-        # try to find out correct indexer, if not type correct raise
-        try:
-            key = self._convert_scalar_indexer(key, axis)
-        except TypeError:
-            # but we will allow setting
-            pass
+        if is_scalar(key):
+            # try to find out correct indexer, if not type correct raise
+            try:
+                key = self._convert_scalar_indexer(key, axis)
+            except TypeError:
+                # but we will allow setting
+                if not setting:
+                    raise
 
         # see if we are positional in nature
         is_int_index = labels.is_integer()
@@ -2032,7 +2036,7 @@ def _get_slice_axis(self, slice_obj: slice, axis: int):
         indexer = self._convert_slice_indexer(slice_obj, axis)
         return self._slice(indexer, axis=axis, kind="iloc")
 
-    def _convert_to_indexer(self, key, axis: int):
+    def _convert_to_indexer(self, key, axis: int, setting: bool = False):
         """
         Much simpler as we only have to deal with our valid types.
         """