Pandas MultiIndex not returning levels and labels

Question

I am learning about pandas MultiIndex() for the first time. Here I have two lists that I want to combine using the MultiIndex() function. the outcome I am expecting should have levels and labels but this is not the case here.

here is my code:

import numpy as np
import pandas as pd

inside = ['a', 'a', 'a', 'b', 'b', 'b']
outside = [1,2,3,1,2,3]
zipped = list(zip(inside, outside))
hier_zipped = pd.MultiIndex.from_tuples(zipped)

hier_zipped

the expected outcome:

MultiIndex(levels = [['a','b'],[1,2,3]], 
           labels = [[0,0,0,1,1,1],[0,1,2,0,1,2]]
           )

the actual outcome:

MultiIndex([('a', 1),
            ('a', 2),
            ('a', 3),
            ('b', 1),
            ('b', 2),
            ('b', 3)],
           )

Answer 1

Your two codes are giving equal objects (Just note that labels should be codes), the representation of the MultiIndex does not show the levels/codes:

pd.MultiIndex(levels=[['a','b'],[1,2,3]], codes=[[0,0,0,1,1,1],[0,1,2,0,1,2]])

Output:

MultiIndex([('a', 1),
            ('a', 2),
            ('a', 3),
            ('b', 1),
            ('b', 2),
            ('b', 3)],
           )

If you want the levels and codes, use:

hier_zipped.levels
# FrozenList([['a', 'b'], [1, 2, 3]]),

hier_zipped.codes
# FrozenList([[0, 0, 0, 1, 1, 1], [0, 1, 2, 0, 1, 2]])