Python Pandas - Get a tuple with the length of each level from MultiIndex

To get a tuple with the length of each level from MultiIndex, use the MultiIndex.levshape property in Pandas. This property returns a tuple where each element represents the number of unique values in the corresponding level.

Creating a MultiIndex

First, let's create a MultiIndex with two levels ?

import pandas as pd

# Create arrays for MultiIndex
arrays = [[1, 2, 3, 4, 5], ['John', 'Tim', 'Jacob', 'Chris', 'Keiron']]

# Create MultiIndex with named levels
multiIndex = pd.MultiIndex.from_arrays(arrays, names=('ranks', 'student'))
print("The Multi-index...\n", multiIndex)

The Multi-index...
MultiIndex([(1,   'John'),
            (2,    'Tim'),
            (3,  'Jacob'),
            (4,  'Chris'),
            (5, 'Keiron')],
           names=['ranks', 'student'])

Getting Level Shapes

Use the levshape property to get the length of each level ?

import pandas as pd

arrays = [[1, 2, 3, 4, 5], ['John', 'Tim', 'Jacob', 'Chris', 'Keiron']]
multiIndex = pd.MultiIndex.from_arrays(arrays, names=('ranks', 'student'))

# Get tuple with length of each level
print("The tuple with the length of each level:", multiIndex.levshape)
print("Number of levels:", multiIndex.nlevels)
print("Levels content:", multiIndex.levels)

The tuple with the length of each level: (5, 5)
Number of levels: 2
Levels content: [[1, 2, 3, 4, 5], ['Chris', 'Jacob', 'John', 'Keiron', 'Tim']]

Example with Duplicate Values

Let's see how levshape works with duplicate values in levels ?

import pandas as pd

# Create MultiIndex with duplicate values
arrays = [[1, 1, 2, 2, 3], ['A', 'B', 'A', 'C', 'B']]
multiIndex = pd.MultiIndex.from_arrays(arrays, names=('level1', 'level2'))

print("MultiIndex with duplicates:")
print(multiIndex)
print("\nLevel shapes:", multiIndex.levshape)
print("Unique values in level 0:", multiIndex.levels[0])
print("Unique values in level 1:", multiIndex.levels[1])

MultiIndex with duplicates:
MultiIndex([(1, 'A'),
            (1, 'B'),
            (2, 'A'),
            (2, 'C'),
            (3, 'B')],
           names=['level1', 'level2'])

Level shapes: (3, 3)
Unique values in level 0: [1, 2, 3]
Unique values in level 1: ['A', 'B', 'C']

Conclusion

The levshape property returns a tuple showing the number of unique values in each level of a MultiIndex. This is useful for understanding the structure and dimensions of hierarchical indices in pandas.