[R] cumsum list..

[Gabor Csardi]

cumsum( mapply(function(i,j) sum(a$data[i:j]), x, y) )

Is this what you want?
Gabor

On Thu, Mar 13, 2008 at 06:02:13AM -0700, yoooooo wrote:
> 
> Hi all, i have the following.. 
> 
> a <- data.frame(data = seq(1,10))
> 
> i have indices:
> x <- c(1, 5, 3, 9)
> y <- c(2, 7, 4, 10)
> 
> I want the cumsum of a[1:2], a[5:7], a[3:4]... 
> 
> is there an elegant way to do it without any loop? Thanks!
> 
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-- 
Csardi Gabor <csardi at rmki.kfki.hu>    UNIL DGM