R help - Oct 2011 - optimize R code: replace for loop

Dear R Users,

at the moment I am trying to optimize an R script.

testvec <- c(0,1,0,1,1,1,1,0,0,1,0,1,0)


sum.testvec <- vector()
tempsum <- 1
for (e in 1:length(testvec)){
sum.testvec[e] <- tempsum+testvec[e]
tempsum <- sum.testvec[e]

}

final.sum <- c(1,sum.testvec)


Is there an option to do something with apply? Unfortunately I am not so
familiar with the apply functions.

Thanks.

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You can vectorize it using cumsum.

cumsum(c(1, testvec))

all.equal(final.sum, cumsum(c(1, testvec)))
> -----Oorspronkelijk bericht-----
> Van: r-help-bounces at r-project.org [mailto:r-help-bounces at
r-project.org]
> Namens Chris82
> Verzonden: woensdag 5 oktober 2011 11:50
> Aan: r-help at r-project.org
> Onderwerp: [R] optimize R code: replace for loop
> 
> Dear R Users,
> 
> at the moment I am trying to optimize an R script.
> 
> testvec <- c(0,1,0,1,1,1,1,0,0,1,0,1,0)
> 
> 
> sum.testvec <- vector()
> tempsum <- 1
> for (e in 1:length(testvec)){
> sum.testvec[e] <- tempsum+testvec[e]
> tempsum <- sum.testvec[e]
> 
> }
> 
> final.sum <- c(1,sum.testvec)
> 
> 
> Is there an option to do something with apply? Unfortunately I am not so
> familiar with the apply functions.
> 
> Thanks.
> 
> --
> View this message in context:
http://r.789695.n4.nabble.com/optimize-R-code-
> replace-for-loop-tp3873945p3873945.html
> Sent from the R help mailing list archive at Nabble.com.
> 
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