Dear R Gurus, Let's get the technical details out of the way first:
Computer: 1.83 GHz MacBook R version 2.5.1 I have a data set that contains the following variables: site, species, total.vines. I need to partition the main data set by site, the further select only those species that occurred at each site. When I select by site (site.name<-subset(data frame,Site=="Site name"), the resulting data frame is normal, containing all the records for that particular site. When I then further select by species, (site.name1<-subset(site.name, Species=c("species 1", "species 2", "species 4", "species 7", "species 8"))), I get an error message: > Warning messages: > 1: longer object length > is not a multiple of shorter object length in: is.na(e1) | is.na(e2) > 2: longer object length > is not a multiple of shorter object length in: `==.default` > (Species, c("ACNE", "ACSA2", "JUNI", "PLOC", "ULAM")) If I then only select for two species instead of five, the error messages disappear HOWEVER, the data will be cut in half, so the new data frame only contains 13 records of species 1 (instead of 26 as in the original) and 12 records of species 2 (instead of the original 24). This is the first time I'm experiencing this problem, as I have used subset on this data several times in the past month. Any ideas on where I'm going wrong? Thanks for your help. Jim Milks Graduate Student Environmental Sciences Ph.D. Program 136 Biological Sciences Wright State University 3640 Colonel Glenn Hwy Dayton, OH 45435 http://www.wright.edu/academics/envsci/ [[alternative HTML version deleted]] ______________________________________________ R-help@stat.math.ethz.ch 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.