Hi Beatriz, I'll guess that you have a number of files with names like this:
Samples_1.txt Samples_2.txt ... Each one can be read with a function like read.table and will return a data frame with default names (V1, V2, ...). You then want to extract the first element (column) of the data frame. If I'm correct, try this: V1s<-list() # nfiles is the number of files you want to read for(i in 1:nfiles) { filename<-paste("Samples_",i,".txt,sep="") # you will probably have to add the appropriate arguments to read.table V1s[[i]]<-read.table(filename)$V1 } The list V1s should contain the first columns of all the data frames read. Jim On Wed, May 25, 2016 at 7:01 AM, Beatriz <aguitatie...@hotmail.com> wrote: > > In my environment I have a data frame called Samples_1.txt. > From this data frame I need to get variable V1. My code doesn't work. > Thanks! > > sprintf("Samples_%s.txt", 1)$V1 > > Note: I need to do it in this way because I have the code into a for loop. > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > 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 -- To UNSUBSCRIBE and more, see 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.