On 11-01-06 12:16 PM, Jarrett Byrnes wrote: > Ah, so, you have factors that are no longer present in the data. I > use a quick function I wrote called purgef to get rid of zombie > factors. > > purgef<-function(x) lapply(x, function(x) x[drop = TRUE]) > > > So, here, before your boxplot > > dat$ageclass <- purgef(dat$ageclass) >
Two points: * the latest version of R has a built-in droplevels() function * the problem here is dropping missing *interaction* terms. I think the OP needs: transform(dat,agesex=droplevels(interaction(ageclass,sex))) (or just dat$agesex = with(dat,droplevels(interaction(ageclass,sex))) boxplot(y~agesex,data=dat) >> > On Jan 6, 2011, at 9:09 AM, Howe, Eric (MNR) wrote: > >> Good day list members, >> >> >> >> I was wondering if anyone knows a way to omit specific columns or >> anova cells from boxplots. >> >> >> >> E.g. I produce a boxplot as: >> >> >> >>> boxplot(y ~ ageclass + sex,data=dat) >> >> >> >> where ageclass has 4 levels (including 1-year-old), and sex has 2 >> levels, but the only males included in the analysis are >> one-year-olds. >> >> The resulting boxplot illustrates differences among age classes of >> females, and between male and female one-year-olds. >> >> However, it has 3 blank columns, corresponding to subadult, young >> adult, and mature age classes of males. >> >> I'd like to exclude those blank columns from the figure. >> >> >> >> Thanks in advance, >> >> >> >> Eric >> >> >> >> >> >> >> [[alternative HTML version deleted]] >> >> _______________________________________________ R-sig-ecology >> mailing list R-sig-ecology@r-project.org >> https://stat.ethz.ch/mailman/listinfo/r-sig-ecology > > _______________________________________________ R-sig-ecology mailing > list R-sig-ecology@r-project.org > https://stat.ethz.ch/mailman/listinfo/r-sig-ecology _______________________________________________ R-sig-ecology mailing list R-sig-ecology@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-ecology
