I should have added TOWER$Tower <- factor(TOWER$Tower)
To the end to convert Tower from an integer to a factor. ---------------------------------------------- David L Carlson Associate Professor of Anthropology Texas A&M University College Station, TX 77843-4352 > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-bounces@r- > project.org] On Behalf Of David L Carlson > Sent: Monday, May 21, 2012 12:30 PM > To: 'Rui Barradas'; 'bdossman' > Cc: r-help@r-project.org > Subject: Re: [R] Loop Help > > Here is a slightly different approach that takes advantage of > recycling: > > # Make 7 data frames > for (i in 1:7) { > assign(paste("TOWER", i, sep=""), data.frame(A=letters[1:4], > X=rnorm(4))) > } > # Add Tower column taking advantage of recyling > tnames <- paste("TOWER", 1:7, sep="") > for (i in 1:7) { > assign(tnames[i], cbind(eval(as.name(tnames[i])), Tower=i)) > } > # Combine them into a single data frame > TOWER <- do.call(rbind, lapply(tnames, as.name)) > > > > -----Original Message----- > > From: r-help-boun...@r-project.org [mailto:r-help-bounces@r- > > project.org] On Behalf Of Rui Barradas > > Sent: Saturday, May 19, 2012 9:04 AM > > To: bdossman > > Cc: r-help@r-project.org > > Subject: Re: [R] Loop Help > > > > Hello, > > > > The error is that you are trying to use the number of rows of a > > character string. > > TOWERS[1], TOWERS[2], etc, are not data frames. Use a print statement > > before the line that throws the error to check it. > > > > Your problem can be solved along the lines of what follows. > > Note that I've put all data frames in a list, it's better to have > them > > kept like that, it makes everything else simpler. > > > > > > # Create a list with some made up data.frames > > towers <- list(TOWER1=data.frame(A=letters[1:4], X=rnorm(4)), > > TOWER2=data.frame(A=LETTERS[1:6], X=runif(6))) > > towers > > > > # In your case this is from TOWER1 to TOWER7 > > TOWERS <- names(towers) > > > > towers.with.id <- lapply(TOWERS, function(i){ > > towers[[ i ]]$Tower <- factor(i) > > towers[[ i ]]}) > > > > > > (Use something other than 'towers.with.id', this is just an example.) > > > > > > #names(towers.with.id) <- TOWERS # (*) See below > > towers.with.id > > do.call(rbind, towers.with.id) > > > > > > (*) Try to run these last three instructions with the marked line > > commented/uncommented. > > It's better to uncomment, maybe after rbind. > > You'll later be able to access the list elements with a syntax like > > > > > > towers.with.id[[ "TOWER2" ]] # full data.frame 2 > > towers.with.id[[ TOWERS[2] ]]$A # just that column > > towers.with.id[[ "TOWER2" ]]$A[3] # third element of that column > > > > > > If you do.call/rbind before, to solve the rbind-ed data.frame's row > > names use > > > > rownames(result) <- seq.int(nrow(result)) > > > > where 'result' is the result of do.call. > > > > Hope this helps, > > > > Rui Barradas > > > > Em 19-05-2012 11:00, r-help-requ...@r-project.org escreveu: > > > Date: Fri, 18 May 2012 16:14:08 -0700 (PDT) > > > From: bdossman<bdoss...@gmail.com> > > > To:r-help@r-project.org > > > Subject: [R] Loop Help > > > Message-ID:<1337382848213-4630555.p...@n4.nabble.com> > > > Content-Type: text/plain; charset=us-ascii > > > > > > Hi all, > > > > > > I am a beginner R user and need some help with a simple loop > > function. > > > > > > Currently, I have seven datasets (TOWER1,TOWER2...TOWER7) that are > > all in > > > the same format (same # of col and headers). I am trying to add a > new > > column > > > (factor) to each dataset that simply identifies the dataset. > > Ultimately, I > > > would like to merge all 7 datasets and need that column to identify > > what > > > rows came from what dataset. > > > > > > Using the code below, I get the error message "Error in rep(i, > > > nrow(TOWER.i)) : invalid 'times' argument" but it doesn't make > sense > > to me > > > since nrow should give an integer value. Any help will be really > > > appreciated. > > > > > > TOWERS<- > > c("TOWER1","TOWER2","TOWER3","TOWER4","TOWER5","TOWER6","TOWER7") > > > > > > for(i in 1:7){ > > > TOWER.i<-TOWERS[i] > > > TOWER<-rep(i,nrow(TOWER.i)) > > > TOWER.i<-cbind(TOWER.i[1:2],TOWER, TOWER.i[2:length(TOWER.i)]) > > > } > > > > ______________________________________________ > > 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. > > ______________________________________________ > 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. ______________________________________________ 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.
