with(attenu, mag + as.numeric(station)) is nearly twice as fast:
> system.time(for(i in 1:1000) with(attenu, mag + as.numeric(station))) user system elapsed 0.05 0.02 0.06 > system.time(for(i in 1:1000) rowSums(cbind(mag, station))) user system elapsed 0.09 0.00 0.10 See ?system.time, ?Rprof and http://code.google.com/p/rbenchmark/ for timing commands. On Sat, Sep 26, 2009 at 11:16 AM, tzygmund mcfarlane <tzygm...@googlemail.com> wrote: > Hi, > > For very large matrices, is this the most efficient way to add two > variables together? > > ############################# > attach(attenu) > new<-rowSums(cbind(mag, station)) > ############################# > > Also, could I be directed to some resources for working with very > large datasets? > > Thanks > > ______________________________________________ > 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.