[R] Newbie question about by()

[Uwe Ligges]

david.beede at mail.doc.gov wrote:
> 
> Dear R list:
> 
> I want to make separate estimates for each level of the variable "group."
> After consulting many sources I am stumped as to why the following does not work:
> 
> > wintemp <- subset(alltemp, winner==1)
> > my.ppr <- function(x)
> +   {
> +    if(nrow(x) >= 50) {
> +    pprfile <- ppr(award~ilogemp, data=x,nterms=5,max.terms=10,optlevel=3)
> +     summary(pprfile)
> +      }
> +    }
> > test.by <- by(wintemp,as.factor(wintemp$group),my.ppr)
> Error in model.frame.default(formula = award ~ ilogemp, data = x) :
>      Object "x" not found
> 
> Any help would be greatly appreciated.
> (I am sure I am misunderstanding some fundamental R concepts.)

It is hard to help, if we don't know what all those variables stand for.
I tried something similar and it worked.
What version of R are you running?

Uwe Ligges
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