[I posted this function to R-help a while ago, but should work the same in
S-PLUS.]
gouter <- function(x, FUN, ...) {
xgrid <- as.list(do.call("expand.grid", x))
names(xgrid) <- NULL
array(do.call(deparse(substitute(FUN)), c(xgrid, list(...))),
dim=sapply(x, length), dimnames=x)
}
## Examples:
> list1<-1:3
> list2<-4:7
> list3<-9:12
> gouter(list(list1, list2, list3), paste)
, , 9
4 5 6 7
1 "1 4 9" "1 5 9" "1 6 9" "1 7 9"
2 "2 4 9" "2 5 9" "2 6 9" "2 7 9"
3 "3 4 9" "3 5 9" "3 6 9" "3 7 9"
, , 10
4 5 6 7
1 "1 4 10" "1 5 10" "1 6 10" "1 7 10"
2 "2 4 10" "2 5 10" "2 6 10" "2 7 10"
3 "3 4 10" "3 5 10" "3 6 10" "3 7 10"
, , 11
4 5 6 7
1 "1 4 11" "1 5 11" "1 6 11" "1 7 11"
2 "2 4 11" "2 5 11" "2 6 11" "2 7 11"
3 "3 4 11" "3 5 11" "3 6 11" "3 7 11"
, , 12
4 5 6 7
1 "1 4 12" "1 5 12" "1 6 12" "1 7 12"
2 "2 4 12" "2 5 12" "2 6 12" "2 7 12"
3 "3 4 12" "3 5 12" "3 6 12" "3 7 12"
Andy
> From: Steve Su
>
> Dear All,
>
> I am trying to write a nice and elegant function in Splus 6.0
> on Windows XP.
> Basically what I am trying to do is this:
>
> list1<-1:3
> list2<-4:7
> list3<-9:12
> list4<-0:2
>
> # If I only have list1 and list2
> outer(list1,list2,"paste")
> # If I have list1, list2 and list3
> outer(outer(list1,list2,"paste"),list3,"paste")
> # If I have list1, list2, list3 and list4
> outer(outer(outer(list1,list2,"paste"),list3,"paste"),list4,"paste")
> # And so forth.....
>
> I am thinking there must be a more elegant solution instead
> of using outer
> recursively? It does not matter if the final output is a
> matrix or array as
> long as I can get all the combinations right. I seem to be
> rather blind at
> the moment to see a better solution than the above!
>
> Thank you for your attention.
>
> Steve.
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> **************************************************************
> **************
> **********
>
> Steve Su (s.su@qut.edu.au)
> Postdoctoral fellow
>
> School of Accountancy
> Queensland University of Technology
>
> Postal Address: Steve Su, School of Accountancy, QUT, PO Box 2434,
> Brisbane,
> Queensland, Australia, 4001.
>
> Phone: +61 7 3864 4357
> Fax: +61 7 3864 1812
> Mobile: 0421 840 586
> .
> _--_|\
> / QUT
> \_.--._/
> v
>
> **************************************************************
> **************
> **********
>
> --------------------------------------------------------------------
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