[R] manipulating longitudinal data in r

[Michael Dewey]

At 08:56 17/11/2012, Kemi Racheal wrote:
>Dear list member,
>
>I have the following data example
>ke <- data.frame(patid=c(1,1,1,2,3,3),a=c(1,2,2,1,1,2))
>
>I want to add another variable b, such that the max of 'a' by id is returned
>i.e data ke becomes
>ke <- data.frame(patid=c(1,1,1,2,3,3),a=c(1,2,2,1,1,2),b=c(2,2,2,1,2,2))
>
>Any help will be appreciated.

Dear Kemi
It is often easier to do some sorts of manipulations on the wide 
format of the data. I appreciate that you can always do it both ways.


>Oluwakemi
>
>
>         [[alternative HTML version deleted]]

Michael Dewey
info at aghmed.fsnet.co.uk
http://www.aghmed.fsnet.co.uk/home.html