Creating multiple datetime columns for every request per PersonID Python

Question

My dataset consists out of two columns, PersonID and Request for application(Aanvraag datum). Some PersonIDs occur multiple times because these persons received multiple request on different dates:

Now I want to create multiple request columns per PersonID. For example if a PersonID occurs three times, then the code creates three columns for three different requests dates. If a PersonID occurs one time, the code assigns NaN to the empty requests. In the end there will be as many columns as the PersonID with the most requests.

Example:

Many thanks!

Does this answer your question? [How can I pivot a dataframe?](https://stackoverflow.com/questions/47152691/how-can-i-pivot-a-dataframe), [pivot-a-dataframe-in-pandas](https://stackoverflow.com/questions/70411391/pivot-a-dataframe-in-pandas/70411430#70411430) — Patryk Kowalski, Dec 20 '21 at 09:14

score 0 · Accepted Answer · answered Dec 20 '21 at 09:16

Use GroupBy.cumcount with DataFrame.set_index and append=True and then Series.unstack with DataFrame.add_prefix:

df1 = (df.set_index(df.groupby(level=0).cumcount().add(1), append=True)['Aanvraag datum']
        .unstack()
        .add_prefix('Aanvraag '))

Creating multiple datetime columns for every request per PersonID Python

1 Answers1