Hi, I am trying to replace a single numeric value in a matrix with a character vector. >mat[5580, 4] [1] 838.1 > mat.r <- replace(mat, mat[5580, 4], "NA") I don't get any errors. However when I go to see if the number at mat[5580, 4] was replaced with "NA" the old number is still there. I don't get any errors. >mat.r[5580, 4] [1] 838.1 Any hints on how to do this? Thanks, MAB [[alternative HTML version deleted]]

On Mon, Oct 1, 2012 at 8:17 PM, Mark B <mablfm at="" gmail.com=""> wrote: > Hi, > I am trying to replace a single numeric value in a matrix with a character > vector. > >>mat[5580, 4] > [1] 838.1 > >> mat.r <- replace(mat, mat[5580, 4], "NA") mat[5580,4]=NA Note that matrices can contain only one type, so you will not be able to put in a character value without your whole matrix being coerced to character (probably not what you want). Hope that helps. Sean > I don't get any errors. However when I go to see if the number at mat[5580, > 4] was replaced with "NA" > the old number is still there. I don't get any errors. > >>mat.r[5580, 4] > [1] 838.1 > > Any hints on how to do this? > Thanks, > > MAB > > [[alternative HTML version deleted]] > > _______________________________________________ > Bioconductor mailing list > Bioconductor at r-project.org > https://stat.ethz.ch/mailman/listinfo/bioconductor > Search the archives: http://news.gmane.org/gmane.science.biology.informatics.conductor

Hi Mark, This question doesn't have anything to do with Bioconductor packages, and should be posed on R-help. In future, please restrict to BioC-related topics. On 10/1/2012 8:17 PM, Mark B wrote: > Hi, > I am trying to replace a single numeric value in a matrix with a character > vector. > >> mat[5580, 4] > [1] 838.1 > >> mat.r<- replace(mat, mat[5580, 4], "NA") > I don't get any errors. However when I go to see if the number at mat[5580, > 4] was replaced with "NA" > the old number is still there. I don't get any errors. > >> mat.r[5580, 4] > [1] 838.1 > > Any hints on how to do this? I believe this is covered in an Introduction to R. In addition, the help for replace says that the first argument should be a vector, so there is no reason to think this will work the way you have used it. That said, there are approximately a bazillion ways to do what you want. Three that readily come to mind are: > mat <- matrix(rnorm(100), 10) > is.na(mat[,1]) <- 3 > mat[4,5] <- NA > mat[,2] <- replace(mat[,2], 5, NA) Note that you don't want to put an "NA" in a numeric matrix, as this will coerce the matrix to character. Instead you want an NA. Best, Jim > Thanks, > > MAB > > [[alternative HTML version deleted]] > > _______________________________________________ > Bioconductor mailing list > Bioconductor at r-project.org > https://stat.ethz.ch/mailman/listinfo/bioconductor > Search the archives: http://news.gmane.org/gmane.science.biology.informatics.conductor -- James W. MacDonald, M.S. Biostatistician University of Washington Environmental and Occupational Health Sciences 4225 Roosevelt Way NE, # 100 Seattle WA 98105-6099