Sibylle -
Since you didn't give a reproducible example, I'll try
to make one that will illustrate what you need to know to
answer your question.
Suppose we have a variable with levels "four","five",
and "six".
> ff = factor(rep(c('four','five','six'),c(5,7,2)))
Since the table() function will report the levels in the
same order as boxplot, I'll use that to illustrate my point:
> table(ff)
ff
five four six
7 5 2
Suppose we want the levels to appear in the order "four",
"five","six":
> table(factor(ff,levels=c('four','five','six')))
four five six
5 7 2
Now suppose we want to list them in the order of their frequencies:
> table(factor(ff,levels=rev(names(table(ff)))))
six four five
2 5 7
In other words, you can have a factor's levels appear in whatever
order you'd like by using the levels= argument to factor.
Hope this helps.
- Phil Spector
Statistical Computing Facility
Department of Statistics
UC Berkeley
spector at stat.berkeley.edu
On Mon, 18 Oct 2010, Sibylle St?ckli wrote:
> Dear R users,
>
>
> x-values (EI) = Adw, EG1, LA1, Ad1, LA2, LA3...(14 levels, insect
> stages)
> y-valus = antpop
>
> within the boxplot function x-values are ordered alphabetically
>
> Idea: x-values ranked by list order (insect stage: Egg stage 1 is
> followed by Larvae 1 and not by Egg stage 2 as it would be in an
> alphabetically order)
>
> Problems with the order(tapply()) function: variable lengths differ
>
> thanks
> Sibylle
>
> R-code (as later insect stages have higher means, ordering was based
> on mean or median...)
> SOPRA<-read.table("SOPRA206_WG_WAE.txt",
na.strings="0", header=TRUE)
> ordered<-order(tapply(SOPRA$antpop, SOPRA$EI, mean))
> boxplot(antpop~ordered, data=SOPRA, boxwex=0.20, at=1:14-0.2,
> scales=list(x=list(rot=45)), notch=TRUE, xlab = "EVENT", ylab =
"DOY",
> ylim = c(100,350), yaxs ="i", col="red", subset=(wg ==
"ctrl"))
> boxplot(antpop~ereignis, data=SOPRA, add=TRUE, boxwex=0.20,
> at=1:14+0.2, xaxt="n", notch=TRUE, col="blue",
subset=(wg == "scen"))
> legend(1,330, c("SOPRA206 WGctrl", "SOPRA206 WGscen"),
fill=c("red",
> "blue"), bty="n")
> text(1,340, "Waedenswil", font=2, pos=4)
>
>
> [[alternative HTML version deleted]]
>
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