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Python Pandas - Rearrange levels using level name in MultiIndex
To rearrange levels using level name in MultiIndex, use the MultiIndex.reorder_levels() method in Pandas. Pass the levels (level names) to be rearranged 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'))Reorder levels of MultiIndex. The "order" parameter is used to set the level name in a form to reorder levels −
print("\nReorder levels in MultiIndex using level name...\n",multiIndex.reorder_levels(order=['student','rank','points']))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))
# Reorder levels of MultiIndex
# The "order" parameter is used to set the level name in a form to reorder levels
print("\nReorder levels in MultiIndex using level name...\n",multiIndex.reorder_levels(order=['student','rank','points']))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([('Peter', 2, 50),
('Chris', 4, 30),
( 'Andy', 3, 40),
('Jacob', 1, 70)],
names=['student', 'rank', 'points'])
Reorder levels in MultiIndex using level name...
MultiIndex([('Peter', 2, 50),
('Chris', 4, 30),
( 'Andy', 3, 40),
('Jacob', 1, 70)],
names=['student', 'rank', 'points'])
Updated on: 19-Oct-2021
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