Dear Rlist I am runing a for loop on a large dataset to do exploring investigation. Code embedded in the loop include the "lm" routine. Unfortunately, for some specification of dependent variable, the loop will be interrupted by error as below:
Error in `contrasts<-`(`*tmp*`, value = "contr.treatment") : contrasts can be applied only to factors with 2 or more levels I suspect this might be caused by missing value which, once removed, will left some factors has value only on one level. It turnss out this is not true. Answers for following two questions appreciated. 1. what might be the possible reason behind the error mesage 2. if I simply want to circumvent this error and keep the for loop going, how should I do that. Regards young ______________________________________________ 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.