[R] Running sum

[Kjetil Brinchmann Halvorsen]

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?


max(cumsum(Y))

Kjetil

>
> Thanks,
> Sean
>
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-- 

Kjetil Halvorsen.

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