Merge branch 'master' into ref-indexing-2

pandas/core/internals/managers.py

@@ -1505,6 +1505,7 @@ def take(self: T, indexer, axis: int = 1, verify: bool = True) -> T:
         -------
         BlockManager
         """
+        # We have 6 tests that get here with a slice
         # TODO: should these be np.intp?
         indexer = (
             np.arange(indexer.start, indexer.stop, indexer.step, dtype="int64")

pandas/tests/frame/indexing/test_setitem.py

@@ -387,9 +387,18 @@ def test_setitem_frame_duplicate_columns(self, using_array_manager):
             ],
             dtype="object",
         )
-        expected[2] = expected[2].astype(np.int64)
-        expected[5] = expected[5].astype(np.int64)
-        expected.columns = cols
+        if using_array_manager:
+            expected.columns = cols
+            # setitem replaces column so changes dtype
+            expected["C"] = expected["C"].astype("int64")
+            # TODO(ArrayManager) .loc still overwrites
+            expected["B"] = expected["B"].astype("int64")
+        else:
+            # do this setting with unique columns to be on the safe side
+            expected[2] = expected[2].astype(np.int64)
+            expected[5] = expected[5].astype(np.int64)
+            expected.columns = cols
+
         tm.assert_frame_equal(df, expected)
 
     def test_setitem_frame_duplicate_columns_size_mismatch(self):