On Mon, Oct 18, 2010 at 9:55 AM, Bond, Stephen <stephen.b...@cibc.com> wrote: > Gabor, > > You are suggesting some very advanced usage that I do not understand, but it > seems this is not what I meant when I said loop. > I have a df with 47k rows and each of these is fed to a 'predict' which will > output about 62 rows, so the number of groups is very large and I implied > that I would go through the 47k x 62 rows with > > For (jj in (set of 47k values)) # tmp.df=big.df[big.df$group==jj,] to subset > # and then sum > > Which is very slow. I discovered that even creating the dataset is super slow > as I use write.table > > The clogging comes from > > write.table(tmp,"predcom.csv",row.names=FALSE,col.names=FALSE,append=TRUE,sep=',') > > Can anybody suggest a faster way of appending to a text file?? > > All comments are appreciated.
If the problem is to sum each row of a matrix then rowSums can do that without a loop. -- Statistics & Software Consulting GKX Group, GKX Associates Inc. tel: 1-877-GKX-GROUP email: ggrothendieck at gmail.com ______________________________________________ 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.
