HI,
Saw your response in Nabble.
Try this:
dat1<-read.table(text="
Subj Trial tt
1 1 1
1 1 2
1 1 3
1 1 4
1 1 5
1 2 1
1 2 2
1 2 3
1 3 1
1 3 2
1 3 3
2 1 1
2 1 2
2 1 3
",sep="",header=TRUE)
res<-do.call(rbind,lapply(split(dat1,list(dat1$Subj,dat1$Trial)),function(x)
x[x[,3]<4,]))
rownames(res)<-1:nrow(res)
res
# Subj Trial tt
#1 1 1 1
#2 1 1 2
#3 1 1 3
#4 2 1 1
#5 2 1 2
#6 2 1 3
#7 1 2 1
#8 1 2 2
#9 1 2 3
#10 1 3 1
#11 1 3 2
#12 1 3 3
A.K.
----- Original Message -----
From: mardijk <van_dijkmaria...@hotmail.com>
To: r-help@r-project.org
Cc:
Sent: Thursday, November 1, 2012 11:18 AM
Subject: [R] Select the last rows of when specific conditions are met.
Hello,
As I am new with R I am completely stuck in resolving a, no doubt, easy
problem.
I have a dataset with an enormous amount of rows and 17 columns. I need to
know per trial and subject number if another variable (tt) exceeds a
maximum. If this is true than the last 5000 rows of that specific trial for
that subject number needs to be deleted.
But I am completely stuck on how to do so. After various attempts I have
finally come up with the following (which obviously does not work).
if (dat["tt"]>6000
){
return(
tail(dattest[,c("Trial", "Subj" )],n=5000) <- NA
}
Can anybody explain what I need to do?
Thank you so much!
--
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Sent from the R help mailing list archive at Nabble.com.
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and provide commented, minimal, self-contained, reproducible code.
