diff --git a/pandas/core/reshape/reshape.py b/pandas/core/reshape/reshape.py index d78e97c6845fe..accb577d5345c 100644 --- a/pandas/core/reshape/reshape.py +++ b/pandas/core/reshape/reshape.py @@ -778,7 +778,7 @@ def _stack_multi_column_index(columns: MultiIndex) -> MultiIndex | Index: levs = ( [lev[c] if c >= 0 else None for c in codes] - for lev, codes in zip(columns.levels[:-1], columns.codes[:-1]) + for lev, codes in zip(columns.levels[:-1], columns.codes[:-1], strict=True) ) # Remove duplicate tuples in the MultiIndex.