See cumsum:
x <- rnorm(10)
cs <- function(X) {
+ N <- length(X)
+ Y <- vector(length=N)
+ Y[1] <- X[1]
+ for (i in 2:N) {
+ Y[i] <- Y[i-1]+X[i]
+ }
+ return(max(Y))
+ }
cs(x)
[1] 3.228554
max(cumsum(x))
[1] 3.228554 Andy
From: Sean Davis
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
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