Hi Ulrik On Sat, Sep 4, 2010 at 12:52 PM, Ulrik Stervbo <ulrik.ster...@gmail.com> wrote: > Dear List, > > When I subset a data.frame, the levels are not re-adjusted (see > example). Why is this? Am I missing out on some basic stuff here?
Only that this issue has come up many times before, and that this list is archived and searchable. Try RSiteSearch("subset drop levels", restrict = c("Rhelp10", "Rhelp08", "Rhelp02")) -Ista > > Thanks > Ulrik > > >> m <- data.frame(gender = c("M", "M","F"), ht = c(172, 186.5, 165), wt = >> c(91,99, 74)) >> dim(m) > [1] 3 3 > >> levels(m$gender) > [1] "F" "M" > >> s <- subset(m, m$gender == "M") >> dim(s) > [1] 2 3 > >> levels(s$gender) > [1] "F" "M" > >> cat <- sapply(s, is.factor); s[cat] <- lapply(s[cat], factor) >> dim(s) > [1] 2 3 > >> levels(s$gender) > [1] "M" > > ______________________________________________ > 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. > -- Ista Zahn Graduate student University of Rochester Department of Clinical and Social Psychology http://yourpsyche.org ______________________________________________ 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.