Reverse tuple to avoid unintended dtype inference

pandas-dev · sanggon6107 · Mar 4, 2025 · Mar 4, 2025 · Mar 4, 2025 · Mar 4, 2025
commit d2e29c0b538d88fd22c31eb27dc15aa0383e7e2e
diff --git a/pandas/core/indexing.py b/pandas/core/indexing.py
@@ -28,7 +28,6 @@

 from pandas.core.dtypes.cast import (
    can_hold_element,
-    find_common_type,
    maybe_promote,
 )
 from pandas.core.dtypes.common import (
@@ -1067,7 +1066,13 @@ def _getitem_lowerdim(self, tup: tuple):

        tup = self._validate_key_length(tup)

-        for i, key in enumerate(tup):
+        # Reverse tuple so that we are indexing along columns before rows
+        # and avoid unintended dtype inference. # GH60600
+        if any(isinstance(ax, MultiIndex) for ax in self.obj.axes):
+            enum = enumerate(tup)
+        else:
+            enum = zip(range(len(tup) - 1, -1, -1), reversed(tup))
+        for i, key in enum:
            if is_label_like(key):
                # We don't need to check for tuples here because those are
                #  caught by the _is_nested_tuple_indexer check above.
@@ -1095,14 +1100,7 @@ def _getitem_lowerdim(self, tup: tuple):
                if com.is_null_slice(new_key):
                    return section
                # This is an elided recursive call to iloc/loc
-                out = getattr(section, self.name)[new_key]
-                # Re-interpret dtype of out.values for loc/iloc[int, list-like].
-                # GH60600
-                if i == 0 and isinstance(key, int) and is_list_like(tup[1]):
-                    dt = self.obj.dtypes.__getitem__(tup[1])
-                    if len(dt) > 0:
-                        out = out.astype(find_common_type(dt.tolist()))
-                return out
+                return getattr(section, self.name)[new_key]

        raise IndexingError("not applicable")