[R] Selecting the first measurement only from a longitudinal sequence

[jim holtman]

Is this what you want:

> x <- read.table(textConnection("ID Time Failuretime Censoringind longitudinalmeasure
+ 1  0     35                  0                123
+ 1  10    35                 0                 120
+ 1   25   35                 1                   123
+ 2   0    23                  0                   100
+ 2   10  23                  0                   111"), header=TRUE)
> do.call(rbind, lapply(split(x, x$ID), function(.grp) .grp[1,]))
  ID Time Failuretime Censoringind longitudinalmeasure
1  1    0          35            0                 123
2  2    0          23            0                 100
>
>
>


On Fri, Jul 25, 2008 at 3:31 PM, john james <dntssa at yahoo.com> wrote:
> Dear R-help mailing list,
>
> I have this problem, I have a joint  longitudinal and survival data of the form say
>
> ID Time Failuretime Censoringind longitudinalmeasure
> 1  0     35                  0                123
> 1  10    35                 0                 120
> 1   25   35                 1                   123
> 2   0    23                  0                   100
> 2   10  23                  0                   111
>
>
> I wish to create a new dataset such that only the first measurement is included.
>
> Also, i will appreciate if there is a function that i could call to do this because I will be applying it too in a simulation settings.
>
> Thank you for your time.
>
> James.
>
>
>
>        [[alternative HTML version deleted]]
>
>
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>



-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem you are trying to solve?