How to use groupby to concatenate strings in python pandas?

I currently have dataframe at the top. Is there a way to use a groupby function to get another dataframe to group the data and concatenate the words into the format like further below using python pandas?

Thanks
[

Answers:

Thank you for visiting the Q&A section on Magenaut. Please note that all the answers may not help you solve the issue immediately. So please treat them as advisements. If you found the post helpful (or not), leave a comment & I’ll get back to you as soon as possible.

Method 1

You can apply join on your column after groupby:

df.groupby('index')['words'].apply(','.join)

Example:

In [326]:
df = pd.DataFrame({'id':['a','a','b','c','c'], 'words':['asd','rtr','s','rrtttt','dsfd']})
df

Out[326]:
  id   words
0  a     asd
1  a     rtr
2  b       s
3  c  rrtttt
4  c    dsfd

In [327]:
df.groupby('id')['words'].apply(','.join)

Out[327]:
id
a        asd,rtr
b              s
c    rrtttt,dsfd
Name: words, dtype: object

Method 2

If you want to save even more ink, you don’t need to use .apply() since .agg() can take a function to apply to each group:

df.groupby('id')['words'].agg(','.join)

OR

# this way you can add multiple columns and different aggregates as needed.
df.groupby('id').agg({'words': ','.join})

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0