[R] Boxplot using Formula

Dieter Menne dieter.menne at menne-biomed.de
Sun Apr 9 11:24:53 CEST 2006

Matt Goff <goff <at> nawwal.org> writes:

> The problem is that boxplot is displaying groups that are empty in the  
> plot.

Call factor() again on the groups, which will drop levels. You can do that in an
extra line, or on-the-fly:

data<-data.frame(values=c(1:25), groups=rep(c("A","B","C","D","E"),
data = subset(data,groups!="C")

boxplot(values~factor(groups), data=data)

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