Example of a simple function to create a nested data frame in python

nest.py

import pandas as pd
from gapminder import gapminder

def nest(grouped_data):
    '''Takes in a grouped data frame'''
    groups = []
    datas = []
    for group in grouped_data.groups:
        groups.append(group)
        datas.append(grouped_data.get_group(group)) 
    
    if len(grouped_data.grouper.names) == 1:
        return pd.DataFrame({grouped_data.grouper.names[0]: groups, 'data': datas})
    else:
        temp = pd.DataFrame({'tmp' : groups})
        temp[grouped_data.grouper.names] = pd.DataFrame(temp['tmp'].tolist()) 
        del temp['tmp']
        temp['data'] = datas
        return temp

# Examples
grouped = gapminder.groupby('continent')
test1 = nest(grouped)
test1

double_group = gapminder.groupby(['continent', 'country'])
test2 = nest(double_group)
test2