[R] Selecting First Incidence from Longitudinal Data

[arun]

Hi,
Try this:
dat1<- read.table(text="
ID    COMPL  SEX  HEREDITY
1    0      1      2
1    0      1      2
1    3      1      2
2    0      0      1
2    1      0      1
2    2      0      1
2    2      0      1
3    0      0      1
3    0      0      1
3    0      0      1
3    0      0      1
3    2      0      1
4    0      1      2
4    0      1      2
",sep="",header=TRUE)
library(plyr)
dat2<- dat1[ddply(dat1,.(ID),summarise,COMPL!=0)[,2],]
 aggregate(.~ID,data=dat2,head,1)
#  ID COMPL SEX HEREDITY
#1  1     3   1        2
#2  2     1   0        1
#3  3     2   0        1
A.K. 




----- Original Message -----
From: Tasnuva Tabassum <t.tasnuva at gmail.com>
To: r-help at r-project.org
Cc: 
Sent: Saturday, February 23, 2013 9:28 AM
Subject: [R] Selecting First Incidence from Longitudinal Data

I have a longitudinal competing risk data of the form:

ID    COMPL  SEX   HEREDITY
1     0       1      2
1     0       1      2
1     3       1      2
2     0       0      1
2     1       0      1
2     2       0      1
2     2       0      1
3     0       0      1
3     0       0      1
3     0       0      1
3     0       0      1
3     2       0      1
4     0       1      2
4     0       1      2.

Where, COMPL= health complication of diabetic patients which has value
labels   as  0= no complication,1=coronary heart disease, 2=retinopathy, 3=
nephropathy.


I want to select only the first complication that occurred to each patient.
What R function can I use?

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