A) Relying on floating point numbers for predictable indexing is a recipe for failure. Convert your floating point numbers to integers before using them to index.
B) Row and column labels are strings, and you are giving numerics to the brackets. You would need to use as.character() on ddr$x and ddr$y in order to utilize labels for indexing. --------------------------------------------------------------------------- Jeff Newmiller The ..... ..... Go Live... DCN:<jdnew...@dcn.davis.ca.us> Basics: ##.#. ##.#. Live Go... Live: OO#.. Dead: OO#.. Playing Research Engineer (Solar/Batteries O.O#. #.O#. with /Software/Embedded Controllers) .OO#. .OO#. rocks...1k --------------------------------------------------------------------------- Sent from my phone. Please excuse my brevity. Daisy Englert Duursma <daisy.duur...@gmail.com> wrote: Hello, I think this is a simple problem but I am not coming up with a simple solution. I think it just an indexing problem. I can easily replace values in a matrix from a dataframe when the dataframe has row and column numbers. In the example below I use row and column names and I can not get it to work #make a matrix where rows and columns are the lat and long for a bounding box of Australia and all elements have the value of -9990 bb<-matrix(c(rep(-9999,691*886)),nrow=691 ,ncol=886,dimnames=list(seq(-10,-44.50,by=-0.05),seq(112,156.25,by=0.05))) #dfr with row names and col names and values to be replaced in the matrix dfr <- data.frame(cbind(x=seq(120,125,by=0.05), y=-25, var.1=1)) #insert the values from the dfr into the matrix bb[dfr$x,dfr$y]<-d$var.1 Thanks for your help, Daisy -- Daisy Englert Duursma Department of Biological Sciences Room E8C156 Macquarie University, North Ryde, NSW 2109 Australia Tel +61 2 9850 9256 _____________________________________________ 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. [[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.