Derek, the 0*m part zeros out everything in the matrix, expect for the NA's, 0*NA=NA by definition. If we add this to the y[ col(m) ] matrix, then NA+anything=NA, but 0+anything=anything.
G. ps. please answer to the list (as well) On Fri, Feb 01, 2008 at 08:52:50AM -0500, Derek Cyr wrote: > > > Thank you, that works very nicely. I am a little curious as to why you > need to do 0*m and add that to y[col(m)] in the second expression. It > works perfectly, but I am just not sure how, lol. Thanks > > D [...] > Actually, you don't need apply. If there are no NA's then it is > very easy: > > m[] <- y[ col(m) ] > > If you want to keep the NA's then it is a bit more tricky: > > m[] <- 0*m + y[ col(m) ] > > > G. > > On Thu, Jan 31, 2008 at 07:03:51PM -0800, dxc13 wrote: > > > > useR's, > > > > Consider: > > y <- c(20, 25, 30) > > > m <- matrix(c(0.0,1,NA,0.5,1.25,0.75, 0.5, NA, > > > NA),byrow=TRUE,nrow=3,ncol=3) > > > m > > [,1] [,2] [,3] > > [1,] 0.0 1.00 NA > > [2,] 0.5 1.25 0.75 > > [3,] 0.5 NA NA > > > > For each numeric value, I want to replace them with their corresponding > > y-value. The result should look like (here, each row represents a > variable > > rather than the columns): > > [,1] [,2] [,3] > > [1,] 20 25 NA > > [2,] 20 25 30 > > [3,] 20 NA NA > > > > Does anyone know how I can do this using apply()? Or is there an easier > > way? Thanks in advance. > > > > Derek > > -- > > View this message in context: > http://www.nabble.com/replacing-values-in-a-matrix-tp15219764p15219764.html > > Sent from the R help mailing list archive at Nabble.com. > > > > ______________________________________________ > > R-help@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. > > -- > Csardi Gabor <[EMAIL PROTECTED]> UNIL DGM > > > > IMPORTANT NOTICE: This e-mail and any attachments may contain confidential > or sensitive information which is, or may be, legally privileged or otherwise > protected by law from further disclosure. It is intended only for the > addressee. If you received this in error or from someone who was not > authorized to send it to you, please do not distribute, copy or use it or any > attachments. Please notify the sender immediately by reply e-mail and delete > this from your system. Thank you for your cooperation. > -- Csardi Gabor <[EMAIL PROTECTED]> UNIL DGM ______________________________________________ R-help@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.
