[R] manipulating longitudinal data in r

[Jeff Newmiller]

Michael, this comment doesn't seem appropriate to the question, since the sample data is a ragged array that requires the addition of NAs to fit into a wide format.
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Sent from my phone. Please excuse my brevity.

Michael Dewey <info at aghmed.fsnet.co.uk> wrote:

>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
>
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