Jim, What I'm getting at is my lack of understanding when manipulating data frame indices. I have tried something like your matrix example with variants of: Bout[ is.na(Bout[,c('bd.n','ht.n','dbh.n')]), ] <- 0
only to receive the following error message: Error in `[<-.data.frame`(`*tmp*`, is.na(Bout[, c("bd.n", "ht.n", "dbh.n")]), : non-existent rows not allowed My questions were not focussed on the assignment value but, on the selection of multiple columns (of a single type) to process. Which is what I meant by concisely. And, lo and behold, in my attempts to reframe my questions I (finally) came upon a solution: Bout[is.na(Bout$bd.n) | is.na(Bout$ht.n) | is.na(Bout$dbh.n), c('bd.n','ht.n','dbh.n')] <- 0 Thank you for your time, DaveT. ************************************* >-----Original Message----- >From: jim holtman [mailto:[EMAIL PROTECTED] >Sent: November 20, 2007 02:25 PM >To: Thompson, David (MNR) >Cc: r-help@r-project.org >Subject: Re: [R] Process multiple columns of data.frame > >It really depends on what you want to set the values that contain NAs >to for the various type of the columns. Do you always want numerics >=0, characters ="", and factors =whatever? Do you want to do this for >all the columns in a dataframe? If you want to it for all the columns >in a matrix, it is easy, since all are the same type, and you are >setting them to zero (e.g., yourMatrix[is.na(yourMatrix)] <- 0). > >You can always write a function that can take in the names of the >columns and then depending on their types set the corresponding >values. So it depends on what you mean by "concisely" and how often >you want to do it. > >On Nov 20, 2007 12:27 PM, Thompson, David (MNR) ><[EMAIL PROTECTED]> wrote: >> Hello, >> >> How do I do the following more concisely? >> Bout[is.na(Bout$bd.n), 'bd.n'] <- 0 >> Bout[is.na(Bout$ht.n), 'ht.n'] <- 0 >> Bout[is.na(Bout$dbh.n), 'dbh.n'] <- 0 >> >> Would the form of such a command be different >> between numeric, character and factor columns? >> >> . . . between data.frames and matrices? >> >> Thanx, DaveT. >> ************************************* >> Silviculture Data Analyst >> Ontario Forest Research Institute >> Ontario Ministry of Natural Resources >> [EMAIL PROTECTED] >> http://ofri.mnr.gov.on.ca >> >> ______________________________________________ >> 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. >> > > > >-- >Jim Holtman >Cincinnati, OH >+1 513 646 9390 > >What is the problem you are trying to solve? > ______________________________________________ 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.