giving a unique code by seeing the first column string and the second column-CodePudding

giving a unique code by seeing the first column string and the second columns string and whenever the first column string change it starts from 1

Example

how can I do this using python?

CodePudding user response：

Something like this could work:

Let's assume your data is stored in the data frame df

Split the data frame based on unique values in the first column string.

dfs = dict(tuple(df.groupby('colummen1')))

for _, df in dfs.items():
    df['id'] = df.groupby(['colummen1','colummun2']).ngroup()   

dfs = [df[1] for df in dfs]
df = pd.concat(dfs)

CodePudding user response：

You can use transform() after groupby like below:

import numpy as np
df = pd.DataFrame({'col1':['keb1', 'keb1','keb1', 'keb2','keb2'],
                   'col2': ['com1', 'com2', 'com3', 'com1', 'com2']})

df['id'] = df.groupby('col1')['col2'].transform(lambda x : np.arange(len(x)) 1)

Output:

>>> df

   col1  col2  id
0  keb1  com1   1
1  keb1  com2   2
2  keb1  com3   3
3  keb2  com1   1
4  keb2  com2   2