Thanks, that did the trick. My "mclgen" function can be written as
mclgen <- function (datamat,catvar) {
ncat <- nlevels(catvar)
perschoice<-as.data.frame(rep(datamat,ncat))
perschoice<-reshape(perschoice,direction="long",
varying=lapply(names(datamat),rep,ncat),
timevar="newy")
perschoice<-perschoice[sort.list(perschoice$id),]
dep<-parse(text=paste("perschoice$",substitute(catvar),sep=""))
perschoice$depvar<-as.numeric(eval(dep)==perschoice$newy)
perschoice
}
I'd still appreciate the help of R-listers on how to use the value of
"catvar" on the left-hand side of an expression within a function
(perschoice$"valueof(catvar)"<-perschoice$newy), and how to get R to
drop the reference category of a factor in an interaction effect
without the main effect (in
"clogit(depvar~occ+occ:educ+occ:black+strata(id),data=pc)").
But many thanks for the help so far!
John Hendrickx
--- Thomas Lumley <[EMAIL PROTECTED]> wrote:
> On Thu, 30 Jan 2003, John Hendrickx wrote:
>
> > The only problem though is the last step, specifying a list of
> varying
> > variables. It should be possible to generate this from
> "names(dset)"
> > but I can't get it right. "as.list(rep(names(dset),2))" produces
> a
> > list with four elements rather than a list with 2 components each
> > containing two elements. "dim()" gives a matrix as a result.
> Could
> > someone show me how to create
> "list(x1=c("X1","X1"),x2=c("X2","X2"))"
> > from "names(dset)"?
>
> lapply(names(dset),rep,2)
> gives
> [[1]]
> [1] "X1" "X1"
>
> [[2]]
> [1] "X2" "X2"
>
> -thomas
>
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