[R] Functions within functions in R and S-Plus
Sundar Dorai-Raj
sundar.dorai-raj at pdf.com
Tue Jun 7 19:11:54 CEST 2005
Victor Gravenholt wrote:
> Sorry to bother you about a S-Plus related problem, but I hope someone
> can help.
> I have tried to "translate" some code from R to S-Plus (I have colleague
> that insists on using S-Plus. And yes, I have tried to make him change
> to R...)
> The following code works out fine in R, but in S-Plus (S-PLUS 6.2 for
> Windows Professional Ed.) I get the error message "Problem in
> est.theta(x): Object "func" not found ".
> I have tried to keep most of the structure in my original problem (but
> simplified it!), so the code could seem a bit strange.
> I suspect that this has something to do with different scoping rules in
> R and S-Plus, but still I have not found a workable solution in S-Plus.
>
> mainfunc <- function(x){
>
> est <- function(x,par){
> abs(sum(par*x))
> }
>
> func <- function(par,x){
> est(x,par)
> }
>
> est.theta <- function(x){
> optimize(func,lower=-10, upper=20,x=x)$minimum
> }
>
> est.theta(x)
>
> }
>
> x <- 1:10
> mainfunc(x)
>
>
>
You need to supply func to est.theta. R uses scoping to find func and
est. S-PLUS scoping is defined differently and cannot, so you must
assign them to the current frame.
is.R <- !is.null(version$language)
mainfunc <- function(x) {
est <- function(x, par) {
abs(sum(par * x))
}
func <- function(par, x) {
est(x, par)
}
est.theta <- function(x) {
optimize(func, lower = -10, upper = 20, x = x)$minimum
}
if(!is.R) {
assign("func", func, frame = 1)
assign("est", est, frame = 1)
}
est.theta(x)
}
mainfunc(1:10)
--sundar
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