Thanks very much for the help. I ended up getting it to work with one small change:
by(foo, foo$V2, function(foo) mean(foo$trust, na.rm=T)) thanks again, Ari -- View this message in context: http://r.789695.n4.nabble.com/help-with-by-command-tp3766285p3779622.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.
