[R] Running sum

Sean Davis sdavis2 at mail.nih.gov
Fri Nov 19 19:08:37 CET 2004

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]

Is there a faster way to do this?


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