Select the last rows of when specific conditions are met.
I really don't understand what you want to achieve and how your data presents itself. You have several combinations of trial/subject which are unique? There is a variable for each such combination that you want to test against (tt)? In addition you have data on each such combination (several sets with 17 columns ) ? or each column is a subject and each row a trial or something along those lines?
On 01.11.2012, at 16:18, mardijk wrote:
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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