Your code is not re-producable. Can you provide a working example using a standard dataset from R? But, you could first try to use compiler package, see ?enableJIT. Another option would be to use doMC/foreach packages if you can run your assignment in the nested loop in parallel, see %dopar%.
On 8 May 2014 21:59, Ludwig Hilger <l.hil...@ku.de> wrote: > Hello everybody, > I have written a nested for-loop, but as length(uc) > 170,000, this would > take VERY long. I have tried to use sapply or something but I cannot get it > to work, I would be happy if someone could point out to write this more > efficiently. Thank you all, > > Ludwig > > ergsens <- data.frame(budget = numeric(500)) > uc <- unique(rftab$startCell) > > for(i in 1:500){ > uniquerates <- rlnorm(n = length(uc), mean = -1.6, sd = 1.7) > for(j in 1:length(uc)){ > rftab$masskg[rftab$startCell == uc[j]] <- uniquerates[j] > } > ergsens$budget[i] <- sum(rftab$masskg, na.rm = TRUE)/1000 > } > > > > > > ----- > Dipl. Geogr. Ludwig Hilger > Wiss. MA > Lehrstuhl für Physische Geographie > Katholische Universität Eichstätt-Ingolstadt > Ostenstraße 18 > 85072 Eichstätt > -- > View this message in context: > http://r.789695.n4.nabble.com/How-can-I-make-this-nested-loop-faster-tp4690209.html > Sent from the R help mailing list archive at Nabble.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. ______________________________________________ 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.