Re: [R] matrix operation

From: Achim Zeileis <Achim.Zeileis_at_wu-wien.ac.at>
Date: Sat 08 Oct 2005 - 08:17:52 EST

On Fri, 07 Oct 2005 18:01:41 -0400 Dhiren DSouza wrote:

> Hello:
>
> I have a matrix 'dat' with 2 columns.
>
> I have the following code:
>
> for (i in 1:nrows(dat))
> {
> if (dat[i,1] < dat[i,2])
> {
> dat[i,2]<-0
> }
>
> else
> {
> dat[i,2]<-1
> }
>
> Is there a way to accomplish this without the for loop?

For this setting
  dat[,2] <- as.numeric(dat[,1] >= dat[,2]) seems to work.

For more complicated tasks look at ifelse().

hth,
Z

> Thank you.
>
> -Dhiren
>
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R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Sat Oct 08 08:29:20 2005

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