Add dataframe column that will represent a 'resetting index'

Asked Jun 19 '20 at 16:43

Active Jun 19 '20 at 16:43

Viewed 15 times

This is what I'm looking for:

Original DF:

    Col1   
0   Dave
1   Dave
2   Mike
3   Mike
4   Mike
5   Jeff

Desired DF:

    Col1   Col2
0   Dave     1
1   Dave     2
2   Mike     1
3   Mike     2
4   Mike     3
5   Jeff     1

Thanks for help!

asked Jun 19 '20 at 16:43

dmd7

1

You can use `groupby` with `cumcount` – Ch3steR Jun 19 '20 at 16:48
1

`df['Col2'] = df.groupby('Col1').cumcount()+1` would do – anky Jun 19 '20 at 16:48

0 Answers0