[R] Why does a custom function called is.numeric.factor break lattice?

[Jeff Newmiller]

You need to read about S3 classes, and either make your custom function behave the way that function needs to behave or use a different function name for your custom function.

I think this is an example of the old saying that if it hurts when you slam your head against the wall, then don't do that.
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Sent from my phone. Please excuse my brevity.

On November 15, 2015 6:22:42 PM PST, sbihorel <Sebastien.Bihorel at cognigencorp.com> wrote:
>Hi,
>
>Pretty much everything is in the title of the post. An example is
>below.
>
>library(lattice)
>data <- 
>data.frame(x=rep(1:10,8),y=rnorm(80),trt=factor(rep(1:4,each=20)),groups=rep(1:8,each=10))
>xyplot <- xyplot(y~x|trt,data,groups=groups)
>
>is.numeric.factor <- function(){
>   print('hello world')
>}
>
>xyplot <- xyplot(y~x|trt,data,groups=groups)
>
>Thanks for shedding some light on this.
>
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