# [R] How to use: library lattice: barchart

P Ehlers ehlers at math.ucalgary.ca
Tue Mar 21 13:00:50 CET 2006

```I think your problem is the definition of abarley. You're making
ayield into a factor. Have a look at str(abarley).

Peter Ehlers

>
> In the help text for the xyplot (library(lattice), help(xyplot)) is an example
> given how one can use barchart:
>
> barchart(yield ~ variety | site, data = barley,
>               groups = year, layout = c(1,6),
>               ylab = "Barley Yield (bushels/acre)",
>               scales = list(x = list(abbreviate = TRUE,
>                             minlength = 5)))
>
> I want my data to be represented just in the same way. But when I try it like
> this:
>
>
> ayield = c(2,3,5,6,3,4,7,8,9,2,3,5,6,1,2,3,4,2,6,8)
> avariety = c(rep("A",5),rep("B",5),rep("C",5),rep("D",5))
> ayear = (c(rep(1931,10),rep(1932,10)))
> asite = c(rep(c("iu","gt","jt","jhzt","tr"),4))
> abarley = data.frame(cbind(ayield,avariety,ayear,asite))
>
> barchart(ayield ~ avariety | asite, data = abarley,groups = ayear, layout =
> c(1,5) )
>
> it looks totaly different and I get the error message:
> "x should be numeric in: bwplot.formula(x = ayield ~ avariety | asite, data =
> list(ayield = c(2,"
>
> What did I do wrong?
> Can anybody help me?
>
> Best regards, thank you very much
>
>