On Tue, Aug 14, 2012 at 5:54 AM, grace <sololo...@hotmail.com> wrote: > Hi, > > I have been running the same code without problem for the last few days, > changing data sets etc with no issue. > Today I changed the covariates for the model and am now getting this error > message: > Error in `contrasts<-`(`*tmp*`, value = contr.funs[1 + isOF[nn]]) : > contrasts can be applied only to factors with 2 or more levels > [snip] >> >> ndvi<-data.frame(x1=factor(c(4, 4, 4, 4, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, >> 3, 4, 4, 4, 4, 3, 3, 4, 4, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, >> 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, >> 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, >> 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, >> 4, 4, 4, 4, 4, 4)), x2=factor(c(4, 4, 4, 4, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, >> 3, 3, 4, 4, 4, 4, 3, 3, 4, 4, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, >> 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, >> 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, >> 3, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, >> 4, 4, 4, 4, 4, 4, 4))) >> [snip] >> >> ndvi<-data.frame(x1=factor(c(3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, >> 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, >> 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, >> 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, >> 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, >> 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3)), x2=factor(c(3, 3, 3, 3, >> 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, >> 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, >> 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, >> 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, >> 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, >> 3, 3)))
Hi Grace, Next time, could you use dput() to make a _small_ reproducible example? Editing out all the symbols added by your mailer and command prompt takes quite some time. You have the idea, but this was a bit much to wade through. Also, you don't need to give the result of tests, since we can run them ourselves if they aren't too time intensive. You might find this of use: http://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example Anyways: take a look at the two code blocks I left: in the first (working) one, you'll see you have factors level 3 and 4, while you only have 3 in the latter data. I believe this is the source of your error: contrasts between groups can't be calculated when there is only one group. Cheers, Michael ______________________________________________ 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.
