[R] row subtraction

Ista Zahn istazahn at gmail.com
Sun Oct 25 23:18:03 CET 2009


If I understand what you're asking this is one (although probably not
the easiest or best) way:

X <- as.data.frame(matrix(runif(50), nrow=10))

X.tmp <- rbind(rep(NA, dim(X)[2]), X[1:(dim(X)[1]-1),])

X.new <- X - X.tmp

-Ista

On Sun, Oct 25, 2009 at 5:45 PM, Marsha Melnyk <mmelnyk at stevens.edu> wrote:
> I don't know if there is a way to do this in R but I want to subtract
> within the same column from different rows.  I want to subtract
> c(r)-c(r-1) and continue down the column until they are all calculated
> and form another column. Again I don't know if R can do this but I
> thought I would ask.
>
> Thanks either way
>
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-- 
Ista Zahn
Graduate student
University of Rochester
Department of Clinical and Social Psychology
http://yourpsyche.org




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