PYTHON

pandas groupby apply list

# import pandas library
import pandas as pd
  
# create a dataframe
df = pd.DataFrame({'a': ['A', 'A', 'B',
                          'B', 'B', 'C',
                          'C', 'D'], 
                    'b': [1, 2, 5,
                          3, 5, 4,
                          8, 6]})
                   
# convert values of each group
# into a list
groups = df.groupby('a')['b'].apply(list)
  
print(groups)
  
# groups store in a new 
# column called listvalues
df1 = groups.reset_index(name 
                         = 'listvalues')
# show the dataframe
df1