Try this:
test2$a <- factor(test2$a)
On Mon, Nov 10, 2008 at 10:33 AM, Ronaldo Reis-Jr.
<chrysopa@gmail.com>wrote:
> Hi,
>
> when I use use subset in a data.frame, all empty levels are maintained in
> the new table.
>
> > test <-
>
data.frame(a=as.factor(rep(c("f1","f2","f3"),10)),b=rep(c(1,2,3),10))
> > summary(test)
> a b
> f1:10 Min. :1
> f2:10 1st Qu.:1
> f3:10 Median :2
> Mean :2
> 3rd Qu.:3
> Max. :3
> > test2 <- subset(test,test$a=="f1")
> > summary(test2)
> a b
> f1:10 Min. :1
> f2: 0 1st Qu.:1
> f3: 0 Median :1
> Mean :1
> 3rd Qu.:1
> Max. :1
>
> Look that the f2 and f3 are in the new table, how to remove all empty
> levels?
>
> Thanks
> Ronaldo
>
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>
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--
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O
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