Hmm, I'm having a fair few difficulties using 'merge' now. I managed to get it to work successfully before, but in this case I'm trying to shorten (as oppose to lengthen as before) a file in relation to a 'master' file.
These are the commands I've been using, followed by the dimensions of the files in question - as you can see, the row numbers of the merged file don't correlate to that of the 'coordinates' file (which is what I'm aiming to get 'merged' equal to): > merge(PopDens.long, coordinates, by=c("Latitude","Longitude"), all = TRUE) -> > merged > dim(PopDens.long); dim(coordinates); dim(merged) [1] 67870 3 [1] 67420 2 [1] 69849 3 One thing I tried was swapping the order of the files in the merge command, but this causes 'merged' to have the same number of rows (69849). Something else I tried was to leave out the 'all = TRUE' command, as I'm essentially attempting the shorten the file, but this makes the output file *too* short! (65441 as opposed to the intended 67420). Again, the same applies when the order of the input files are swapped. > merge(PopDens.long, coordinates, by=c("Latitude","Longitude")) -> merged > dim(PopDens.long); dim(coordinates); dim(merged) [1] 67870 3 [1] 67420 2 [1] 65441 3 Am I doing something obviously wrong? I'm pretty certain that 'coordinates' is a subset of 'PopDens.long' - so there should be equal numbers of common values when merged. Is there perhaps a more suitable function I could use, or a way of performing checks to see where I might be going wrong?! Many thanks, Steve _________________________________________________________________ 100’s of Nikon cameras to be won with Live Search ______________________________________________ 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.