To merge the values of common columns in a data frame

There is one data frame consisting of three columns: group, po, and part

import pandas as pd

df = pd.DataFrame({'group':[1,1,1,1,1,1,2,2,2,2,3,3],
       'po':['1a','1b','','','','','2a','2b','2c','','3a',''],
       'part':['a','b','c','d','e','f','g','h','i','j','k','l']})

by group column,
Po columns are common parts and I want to display them continuously using a slash(‘/’)

like below dataframe

What should I do?

>Solution :

You can group the po values by group, aggregating them using join (with filter to discard empty values):

df['po'] = df.groupby('group')['po'].transform(lambda g:'/'.join(filter(len, g)))
df

Output:

    group        po part
0       1     1a/1b    a
1       1     1a/1b    b
2       1     1a/1b    c
3       1     1a/1b    d
4       1     1a/1b    e
5       1     1a/1b    f
6       2  2a/2b/2c    g
7       2  2a/2b/2c    h
8       2  2a/2b/2c    i
9       2  2a/2b/2c    j
10      3        3a    k
11      3        3a    l