How to make a multi-index in Pandas?

To make a multi-index in Pandas, we can use groupby with list of columns.

Steps

• Create a two-dimensional, size-mutable, potentially heterogeneous tabular data, df.

• Print the input DataFrame.

• Print the index of DataFrame count.

• Use groupby to get different levels of a hierarchical index and count it.

• Print the mulitindex set in step 4.

Example

 Live Demo

import pandas as pd

df = pd.DataFrame(
   {
      "x": [5, 2, 1, 9],
      "y": [4, 1, 5, 10],
      "z": [4, 1, 5, 0]
   }
)
print "Input DataFrame is:
", df
print "\nDefault index: ", df.count().index

df1 = df.groupby(["x", "y"]).count()
print "\nMulti index is like: 
", df1.index

Output

Input DataFrame is:
   x  y  z
0  5  4  4
1  2  1  1
2  1  5  5
3  9 10  0

Default index: Index(['x', 'y', 'z'], dtype='object')

Multi index is like:
MultiIndex([(1, 5),
   (2, 1),
   (5, 4),
   (9, 10)],
names=['x', 'y'])