MultiIndex contains()/in operator throws an IndexError for large multiindices · Issue #10645 · pandas-dev/pandas (original) (raw)

For a small multiindex the in operator works

mi = pd.MultiIndex.from_arrays([range(100),range(100)])
(1000001,0) in mi

For a large multiindex the in operator throws an IndexError

mi = pd.MultiIndex.from_arrays([range(1000000),range(1000000)])
(1000001,0) in mi