[R] For loop

[PIKAL Petr]

Hi

> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of bibek sharma
> Sent: Friday, November 30, 2012 5:00 PM
> To: R-help at r-project.org
> Subject: [R] For loop
> 
> Hello user,
> I have large data containing  subject id, time and response where
> subjects are measured repeatedly. However some time are duplicates. I
> only want data with unique time points per id. I mean if time is
> repeated, then take only one.

Which one? The first one?

aggregate(test$res, list(time=test$time, id=test$id), function(x) x[1])

Regards
Petr


> Here is a sample data.
> 
> id	time 	res
> 1	2	0.64
> 1	3	0.78
> 1	3	6.5
> 1	3	4.5
> 1	4	4
> 1	5	3.4
> 2	10	5.7
> 2	11	5.8
> 2	11	9.3
> 2	11	3.4
> 2	12	3.4
> 2	13	6.7
> 3	3	5.6
> 3	3	3.4
> 3	4	2.3
> 3	5	5.6
> 3	12	9.8
> 3	10	7
> 3	24	6
> 3	16	4
> 
> for 1st subject I want this,
> 
> id	time 	res
> 1	2	0.64
> 1	3	0.78
> 1	4	4
> 1	5	3.4
> Any suggestions are much appreciated!
> Thanks,
> Bikek
> 
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