How to use groupby to concatenate strings in python pandas?

Question

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

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Answer 1

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})