Python - Stacking a multi-level column in a Pandas DataFrame

To stack a multi-level column, use the stack() method. At first, import the required library −

import pandas as pd

Create a multi-level column −

items = pd.MultiIndex.from_tuples([('Maths', 'Mental Maths'),('Maths', 'Discrete Mathematics'),('Maths', 'Applied Mathematics')]) 

Now, create a DataFrame and set multi-level columns we set above −

dataFrame = pd.DataFrame([[67, 86, 78], [56, 92, 97], [92, 95, 91]],index=['John', 'Tom', 'Henry'],columns=items)

Stack the multi-level column −

dataframe.stack()

Example

Following is the complete code −

import pandas as pd # multi-level columns items = pd.MultiIndex.from_tuples([('Maths', 'Mental Maths'),('Maths', 'Discrete Mathematics'), ('Maths', 'Applied Mathematics')]) # creating a DataFrame dataFrame = pd.DataFrame([[67, 86, 78], [56, 92, 97], [92, 95, 91]],index=['John', 'Tom', 'Henry'],columns=items) # DataFrame print"DataFrame...\n",dataFrame # stack multi-level columns print"\nStacking...\n",dataFrame.stack()

Output

This will produce the following output −

DataFrame...            Maths       Mental Maths  Discrete Mathematics  Applied Mathematics John            67                    86                   78 Tom             56                    92                   97 Henry           92                    95                   91 Stacking...                             Maths John   Applied Mathematics     78        Discrete Mathematics    86        Mental Maths            67 Tom    Applied Mathematics     97        Discrete Mathematics    92        Mental Maths            56 Henry Applied Mathematics 91 Discrete Mathematics 95 Mental Maths 92