From: jim holtman <jholtman_at_gmail.com>

Date: Mon, 28 Jul 2008 09:43:37 -0400

> x[is.na(x)] <- 0

*> x
*

Date: Mon, 28 Jul 2008 09:43:37 -0400

[1,] 1 NA NA 2 1 2 [2,] 2 2 2 NA 2 2 [3,] 2 2 NA NA 1 2 [4,] NA 1 2 1 2 1 [5,] 1 1 NA 2 NA NA [6,] NA 1 NA 1 2 NA

> x[is.na(x)] <- 0

[,1] [,2] [,3] [,4] [,5] [,6]

[1,] 1 0 0 2 1 2 [2,] 2 2 2 0 2 2 [3,] 2 2 0 0 1 2 [4,] 0 1 2 1 2 1 [5,] 1 1 0 2 0 0 [6,] 0 1 0 1 2 0

Maybe you should read the Intro To R to understand how vectorization works.

Same way with your last loop:

x[is.na(x[,4]), 4] <- 0

On Mon, Jul 28, 2008 at 9:15 AM, Denise Xifara
<dionysia-kiara.xifaras_at_st-hildas.ox.ac.uk> wrote:

> Dear All and Mark,

*>
**> Given a dataset that I have called dat, I was hoping to speed up the
**> following loop:
**>
**> for(i in 1:835353){
**> for(j in 1:86){
**> if (is.na(dat[i,j])==TRUE){dat[i,j]<-0 }}}
**> Actually I am also having a memory problem. I get the following:
**>
**> Error: cannot allocate vector of size 3.2 Mb
**> In addition: Warning messages:
**> 1: In dat[i, j] <- 0 :
**> Reached total allocation of 1535Mb: see help(memory.size)
**> 2: In dat[i, j] <- 0 :
**> Reached total allocation of 1535Mb: see help(memory.size)
**> 3: In dat[i, j] <- 0 :
**> Reached total allocation of 1535Mb: see help(memory.size)
**> 4: In dat[i, j] <- 0 :
**> Reached total allocation of 1535Mb: see help(memory.size)
**>
**> If I try and apply the loop just to a particular column, rather than the
**> whole dataset, so that I dont have the memory problem, ie
**>
**> for(i in 1:835353){
**> if (is.na(dat[i,4])==TRUE){dat[i,4]<-0 }}
**>
**> it takes ridiculously long to process, so I was hoping that there would be a
**> quicker way to do this.
**>
**> Thank you all very much for the help,
**> Denise
**>
**> [[alternative HTML version deleted]]
**>
**> ______________________________________________
**> R-help_at_r-project.org mailing list
**> https://stat.ethz.ch/mailman/listinfo/r-help
**> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
**> and provide commented, minimal, self-contained, reproducible code.
**>
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-- Jim Holtman Cincinnati, OH +1 513 646 9390 What is the problem you are trying to solve? ______________________________________________ R-help_at_r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.Received on Mon 28 Jul 2008 - 13:59:07 GMT

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