REF: simplify Block.setitem

pandas/core/indexers/utils.py

@@ -104,26 +104,23 @@ def is_scalar_indexer(indexer, ndim: int) -> bool:
     return False
 
 
-def is_empty_indexer(indexer, arr_value: ArrayLike) -> bool:
+def is_empty_indexer(indexer) -> bool:
     """
     Check if we have an empty indexer.
 
     Parameters
     ----------
     indexer : object
-    arr_value : np.ndarray or ExtensionArray
 
     Returns
     -------
     bool
     """
     if is_list_like(indexer) and not len(indexer):
         return True
-    if arr_value.ndim == 1:
-        if not isinstance(indexer, tuple):
-            indexer = (indexer,)
-        return any(isinstance(idx, np.ndarray) and len(idx) == 0 for idx in indexer)
-    return False
+    if not isinstance(indexer, tuple):
+        indexer = (indexer,)
+    return any(isinstance(idx, np.ndarray) and len(idx) == 0 for idx in indexer)
 
 
 # -----------------------------------------------------------

pandas/core/indexing.py

@@ -1883,7 +1883,7 @@ def _setitem_single_column(self, loc: int, value, plane_indexer):
         elif (
             is_array_like(value)
             and is_exact_shape_match(ser, value)
-            and not is_empty_indexer(pi, value)
+            and not is_empty_indexer(pi)
         ):
             if is_list_like(pi):
                 ser = value[np.argsort(pi)]
@@ -2092,7 +2092,7 @@ def ravel(i):
             # we have a frame, with multiple indexers on both axes; and a
             # series, so need to broadcast (see GH5206)
             if sum_aligners == self.ndim and all(is_sequence(_) for _ in indexer):
-                if is_empty_indexer(indexer[0], ser._values):
+                if is_empty_indexer(indexer[0]):
                     return ser._values.copy()
                 ser = ser.reindex(obj.axes[0][indexer[0]], copy=True)._values
 

pandas/core/internals/array_manager.py

@@ -1280,6 +1280,8 @@ def setitem(self, indexer, value):
         See `setitem_inplace` for a version that works inplace and doesn't
         return a new Manager.
         """
+        if isinstance(indexer, np.ndarray) and indexer.ndim > self.ndim:
+            raise ValueError(f"Cannot set values with ndim > {self.ndim}")
         return self.apply_with_block("setitem", indexer=indexer, value=value)
 
     def idelete(self, indexer) -> SingleArrayManager:

pandas/core/internals/blocks.py

@@ -49,7 +49,6 @@
     is_1d_only_ea_dtype,
     is_1d_only_ea_obj,
     is_dtype_equal,
-    is_extension_array_dtype,
     is_interval_dtype,
     is_list_like,
     is_string_dtype,
@@ -911,37 +910,26 @@ def setitem(self, indexer, value):
         `indexer` is a direct slice/positional indexer. `value` must
         be a compatible shape.
         """
-        transpose = self.ndim == 2
-
-        if isinstance(indexer, np.ndarray) and indexer.ndim > self.ndim:
-            raise ValueError(f"Cannot set values with ndim > {self.ndim}")
 
         # coerce None values, if appropriate
         if value is None:
             if self.is_numeric:
                 value = np.nan
 
         # coerce if block dtype can store value
-        values = cast(np.ndarray, self.values)
         if not self._can_hold_element(value):
             # current dtype cannot store value, coerce to common dtype
             return self.coerce_to_target_dtype(value).setitem(indexer, value)
 
         # value must be storable at this moment
-        if is_extension_array_dtype(getattr(value, "dtype", None)):
-            # We need to be careful not to allow through strings that
-            #  can be parsed to EADtypes
-            arr_value = value
-        else:
-            arr_value = np.asarray(value)
-
-        if transpose:
+        values = cast(np.ndarray, self.values)
+        if self.ndim == 2:
             values = values.T
 
         # length checking
         check_setitem_lengths(indexer, value, values)
 
-        if is_empty_indexer(indexer, arr_value):
+        if is_empty_indexer(indexer):
             # GH#8669 empty indexers, test_loc_setitem_boolean_mask_allfalse
             pass
 

pandas/core/internals/managers.py

@@ -334,6 +334,9 @@ def setitem(self: T, indexer, value) -> T:
 
         For SingleBlockManager, this backs s[indexer] = value
         """
+        if isinstance(indexer, np.ndarray) and indexer.ndim > self.ndim:
+            raise ValueError(f"Cannot set values with ndim > {self.ndim}")
+
         return self.apply("setitem", indexer=indexer, value=value)
 
     def putmask(self, mask, new, align: bool = True):