pandas group by and assign a group id then ungroup

Question

I have a large data set in the following format:

id, socialmedia
1, facebook
2, facebook
3, google
4, google
5, google
6, twitter
7, google
8, twitter
9, sn         


        

Answer 1

You can use sklearn.preprocessing.LabelEncoder method:

In [79]: from sklearn.preprocessing import LabelEncoder

In [80]: le = LabelEncoder()

In [81]: df['groupId'] = le.fit_transform(df['socialmedia'])+1

In [82]: df
Out[82]:
    id socialmedia  groupId
0    1    facebook        1
1    2    facebook        1
2    3      google        2
3    4      google        2
4    5      google        2
5    6     twitter        4
6    7      google        2
7    8     twitter        4
8    9    snapchat        3
9   10     twitter        4
10  11    facebook        1