Thanks for the code Andy -- there seams to be no 'nice' way to do
this. The use of 'with' does not work in the context I'm thinking about
(as John Fox suggested to the list, and Douglas Grove personally).
Thanks, Gardar
At 02:50 PM 4/14/2004 -0400, Liaw, Andy wrote:
>What you are asking for doesn't even work at the R prompt, let alone inside
>a function. The _really_ ugly kludge I manage to come up with is to
>manually assign the components of the list (or variables in the data frame)
>into the function's environment:
>
>f <- function(mylist=list(a=1:5)) {
> nm <- names(mylist)
> for (i in seq(along=nm)) {
> assign(nm[i], mget(nm[i], envir=NULL, ifnotfound=mylist[i]))
> }
> sapply(names(mylist), function(x) print(get(x)))
> ls()
>}
>
>Here are a couple of tests:
>
> > f()
>$a
>[1] 1 2 3 4 5
>
>[1] "a" "i" "mylist" "nm"
> > f(list(b=5:1, z="ha!"))
>$b
>[1] 5 4 3 2 1
>
>$z
>[1] "ha!"
>
>[1] "b" "i" "mylist" "nm" "z"
>
>Andy
>
> > From: Gardar Johannesson
> >
> > I'm trying to find a good way of attaching a list within a
> > function such
> > that the attached variables (the list's members) precede the global
> > environment (.GlobalEnv) in the search list. Here is a
> > non-working example
> > using attach(), which hopefully explains better what I'm trying to do:
> >
> > > foo <- function(x=0, input=list(a=10)) {
> > + attach(input)
> > + on.exit(detach(input))
> > + print(search())
> > + print(a)
> > + }
> > >
> > > a
> > Error: Object "a" not found
> > > foo() ## this prints out a = 10
> > [1] ".GlobalEnv" "input" "package:methods"
> > "package:stats"
> > [5] "package:graphics" "package:utils" "Autoloads"
> > "package:base"
> > [1] 10
> > >
> > > a <- 0
> > > foo() ## this prints out a = 0, not a = 10
> > [1] ".GlobalEnv" "input" "package:methods"
> > "package:stats"
> > [5] "package:graphics" "package:utils" "Autoloads"
> > "package:base"
> > [1] 0
> > >
> >
> >
> > Thanks,
> >
> > Gardar
> >
> >
> > ___________________________________________________________________
> > Gardar Johannesson
> > Lawrence Livermore National Laboratory
> > 7000 East Avenue, L-229
> > Livermore, CA 94550
> >
> > [EMAIL PROTECTED]
> > Tel: (925) 422-3901, Fax: (925) 422-4141
> > [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > [EMAIL PROTECTED] mailing list
> > https://www.stat.math.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide!
> > http://www.R-project.org/posting-guide.html
> >
> >
>
>
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Gardar Johannesson
Lawrence Livermore National Laboratory
7000 East Avenue, L-229
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[EMAIL PROTECTED]
Tel: (925) 422-3901, Fax: (925) 422-4141
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