Running sum
On Fri, 2004-11-19 at 13:08 -0500, Sean Davis wrote:
I have vector X of length N that I want to have a running sum for
(called Y). I just need max(Y). I do this with a "for" loop like so:
Y <- vector(length=N)
Y[1] <- X[1]
for (i in 2:N) {
Y[i] <- Y[i-1]+X[i]
}
return(max(Y))
Is there a faster way to do this?
Thanks,
Sean
Something like:
cumsum(1:10)
[1] 1 3 6 10 15 21 28 36 45 55
max(cumsum(1:10))
[1] 55 Does that help? Marc Schwartz