Python Pandas - Swap levels of a MultiIndex

To swap levels of a MultiIndex, use the swaplevel() method in Pandas. The levels to be swapped should be mentioned as arguments.

At first, import the required libraries −

import pandas as pd

MultiIndex is a multi-level, or hierarchical, index object for pandas objects. Create arrays −

arrays = [[2, 4, 3, 1], ['Peter', 'Chris', 'Andy', 'Jacob'], [50, 30, 40, 70]]

The "names" parameter sets the names for each of the index levels. The from_arrays() is used to create a MultiIndex −

multiIndex = pd.MultiIndex.from_arrays(arrays, names=('rank', 'student', 'points'))

Swap levels of MultiIndex using swaplevel(). The 1st parameter is the first level of index to be swapped. The 2nd parameter is the second level of index to be swapped −

print("\nSwap levels in MultiIndex...\n",multiIndex.swaplevel(0,2))

Example

Following is the code −

import pandas as pd

# MultiIndex is a multi-level, or hierarchical, index object for pandas objects
# Create arrays
arrays = [[2, 4, 3, 1], ['Peter', 'Chris', 'Andy', 'Jacob'], [50, 30, 40, 70]]

# The "names" parameter sets the names for each of the index levels
# The from_arrays() is used to create a MultiIndex
multiIndex = pd.MultiIndex.from_arrays(arrays, names=('rank', 'student', 'points'))

# display the MultiIndex
print("The MultiIndex...\n",multiIndex)

# get the levels in MultiIndex
print("\nThe levels in MultiIndex...\n",multiIndex.levels)

# swap levels of MultiIndex using swaplevel()
# The 1st parameter is the first level of index to be swapped
# The 2nd parameter is the second level of index to be swapped
print("\nSwap levels in MultiIndex...\n",multiIndex.swaplevel(0,2))

Output

This will produce the following output −

The MultiIndex...
MultiIndex([(2, 'Peter', 50),
            (4, 'Chris', 30),
            (3,  'Andy', 40),
            (1, 'Jacob', 70)],
            names=['rank', 'student', 'points'])

The levels in MultiIndex...
   [[1, 2, 3, 4], ['Andy', 'Chris', 'Jacob', 'Peter'], [30, 40, 50, 70]]

Swap levels in MultiIndex...
MultiIndex([(50, 'Peter', 2),
            (30, 'Chris', 4),
            (40, 'Andy', 3),
            (70, 'Jacob', 1)],
            names=['points', 'student', 'rank'])