If poproh.3 was your dataset as a data.frame (an object with row and column dimensions), you need a comma following the row selection (sample(...)) to indicate that you want to select those rows and all columns:
newsample <-poprho.3[sample(1:10000,100),] # note the last comma in the brackets General use is: my.data.frame[rows,columns] Where either rows or columns (or both) can be left blank to indicate that you want all of them. Similarly, a selection of the first column would have been (comma followed by column number): newsample <-poprho.3[sample(1:10000,100),1] That's why your: newsample <-as.matrix(nameofdataset[sample(1:10000,100),]) worked; the as.matrix wasn't necessary to simply sample the data. Cheers, Jeff. On Tue, Oct 5, 2010 at 3:54 AM, Jumlong Vongprasert <jumlong.u...@gmail.com> wrote: > Dear Jeffrey. > I used "newsample <-as.matrix(nameofdataset[sample(1:10000,100),])". > Now it include all 2 variable. > Thank you for your answer to inspire. > Jumlong > > 2010/10/5 Jeffrey Spies <jsp...@virginia.edu> >> >> We'll probably need much more info, but this should get you started: >> >> nameOfDataSet[sample(1:10000, 100),] >> >> You can replace the 10000 with dim(nameOfDataSet)[1] to make it more >> dynamic. >> >> Jeff. >> >> On Tue, Oct 5, 2010 at 3:07 AM, Jumlong Vongprasert >> <jumlong.u...@gmail.com> wrote: >> > Dear all. >> > I have data with 2 variable x,y size 10000. >> > I want to sampling from this data with size 100. >> > How I can do it. >> > THANK. >> > >> > -- >> > Jumlong Vongprasert >> > Institute of Research and Development >> > Ubon Ratchathani Rajabhat University >> > Ubon Ratchathani >> > THAILAND >> > 34000 >> > >> > [[alternative HTML version deleted]] >> > >> > ______________________________________________ >> > 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. >> > > > > > -- > Jumlong Vongprasert > Institute of Research and Development > Ubon Ratchathani Rajabhat University > Ubon Ratchathani > THAILAND > 34000 > ______________________________________________ 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.