I'm not sure if I understand correct, but maybe something like: apply(dat,2,function(x) sum(x[x<0]))
Please do read the posting guide and post a small, working example!!! Bart Rheannon wrote: > > Could anyone tell me a better way to achieve the output of this for loop? > It seems to run quite slow. I'm sure there must be a more consise way to > sum from FN to LN, excluding positive values, for each row. > > #sum between FN and LN, excluding positive values > for(i in 1:R){ > for(j in FN[i]:LN[i]){ > if(Temp[i,j]<0) > sum[i] <- sum[i] + sum(Temp[i,j])}} > > Cheers, > R > -- View this message in context: http://www.nabble.com/how-to-speed-up-this-for-loop--tp18579577p18584610.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.