How do I collapse categorical data into a single record in R or Python?

Question

I have a data set structured in this fashion:

ID   Code
1     A
1     B   
1     C
2     A
2     C
3     B
3     C

However, I would like it to look like:

ID  Codes
1   A B C
2   A C
3   B C

Is there an easy way to do this in R or Python? Thanks!

Answer 1

In Python with Pandas you can do:

import pandas as pd

df = pd.read_clipboard() # from your sample

df
   ID Code
0   1    A
1   1    B
2   1    C
3   2    A
4   2    C
5   3    B
6   3    C

---

df.groupby('ID').agg(lambda x: ' '.join(x['Code']))

     Code
ID       
1   A B C
2     A C
3     B C