[R] Select the last rows of when specific conditions are met.

[mardijk]

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!






--
View this message in context: http://r.789695.n4.nabble.com/Select-the-last-rows-of-when-specific-conditions-are-met-tp4648133.html
Sent from the R help mailing list archive at Nabble.com.