whatsnew, GH ref

Author: jbrockmendel

doc/source/whatsnew/v1.5.0.rst

@@ -212,6 +212,7 @@ Indexing
 - Bug in :meth:`DataFrame.iloc` where indexing a single row on a :class:`DataFrame` with a single ExtensionDtype column gave a copy instead of a view on the underlying data (:issue:`45241`)
 - Bug in :meth:`Series.__setitem__` with a non-integer :class:`Index` when using an integer key to set a value that cannot be set inplace where a ``ValueError`` was raised insead of casting to a common dtype (:issue:`45070`)
 - Bug when setting a value too large for a :class:`Series` dtype failing to coerce to a common type (:issue:`26049`, :issue:`32878`)
+- Bug in :meth:`loc.__setitem__` treating ``range`` keys as positional instead of label-based (:issue:`45479`)
 -
 
 Missing

pandas/core/indexing.py

@@ -665,7 +665,7 @@ def _get_setitem_indexer(self, key):
                 return self._convert_tuple(key)
 
         if isinstance(key, range):
-            # test_loc_setitem_range_key
+            # GH#45479 test_loc_setitem_range_key
             key = list(key)
 
         return self._convert_to_indexer(key, axis=0)

pandas/tests/indexing/test_loc.py

@@ -1556,7 +1556,7 @@ def test_loc_setitem_cast3(self):
         assert df.dtypes.one == np.dtype(np.int8)
 
     def test_loc_setitem_range_key(self, frame_or_series):
-        # don't treat range key as positional
+        # GH#45479 don't treat range key as positional
         obj = frame_or_series(range(5), index=[3, 4, 1, 0, 2])
 
         values = [9, 10, 11]