How could I select the rows of a dataset that have the maximum value in one variable and to do this nested in another variable. It is a dataframe in long format with repeated measures per subject.
I was not successful using aggregate, because one of the columns has character values (and/or possibly because of another reason).
I would like to transfer something like this:
subject time.ms V3
1 1 stringA
1 12 stringB
1 22 stringC
2 1 stringB
2 14 stringC
2 25 stringA
?.
To something like this:
subject time.ms V3
1 22 stringC
2 25 stringA
?
Thank you very much for you help!
Miriam
