Hi Folks, I'm trying to find a way to remove all terms in a formula that contain a particular interaction.
For example, in the formula below, I'd like to remove all terms that contain the b:c interaction. > attributes(terms( ~ a*b*c*d))$term.labels [1] "a" "b" "c" "d" "a:b" "a:c" [7] "b:c" "a:d" "b:d" "c:d" "a:b:c" "a:b:d" [13] "a:c:d" "b:c:d" "a:b:c:d" My eventual use is to fit models with the reduced formulas. For example: > my_df = data.frame( iv = runif(100), a=runif(100), b=runif(100), c=runif(100), d=runif(100)) > lm(iv ~ a*b*c*d, data=my_df) I can remove particular terms with update(), but I don't see a way to remove all terms that contain a given combination of factors. Any help would be greatly appreciated. Thanks! Allie ______________________________________________ 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.
