CODEWITHSUNDEEP
pythonpandasnumpydataframemulti-index
Felix
Felix

Reputation: 1905

Get specific index from MultiIndex of Pandas data frame as list

I want to to get a specific index of a Pandas data frame with a MultiIndex as a list.

Given the example

import pandas as pd; import numpy as np
np.random.seed(42)
df = pd.DataFrame(np.random.randint(5, size=(5, 4)), columns=list('ABCD'))
df.set_index(['A', 'B'], inplace=True)

in which df is defined as

     C  D
A B
3 4  2  4
4 1  2  2
2 4  3  2
4 1  3  1
3 4  0  3

I want to extract

[4 1 4 1 4]

which corresponds to the second index B. How can this be done?

Upvotes: 0

Views: 105

Answers (2)

Felix
Felix

Reputation: 1905

This solution uses stacking through np.stack() and slicing:

np.stack(df.index.values, axis=0)[:,1]

Upvotes: 0

BENY
BENY

Reputation: 323226

Using get_level_values

df.index.get_level_values(level=1).tolist()
Out[1040]: [4, 1, 4, 1, 4]

Or reset_index

df.reset_index(level=1).B.tolist()
Out[1041]: [4, 1, 4, 1, 4]

Upvotes: 4

Related Questions