Extracting specific arguments from "..."

I would use two because it does not force the evaluation of the other arguments in the ... list.



On Sun, Jan 5, 2025, 13:00 Bert Gunter <bgunter.4567 at gmail.com> wrote:

Consider:

f1 <- function(...){
  one <- list(...)[['a']]
  two <- ...elt(match('a', ...names()))
  c(one, two)
}
## Here "..." is an argument list with "a" somewhere in it, but in an
unknown position.

f1(b=5, a = 2, c=7)

[1] 2 2

Which is better for extracting a specific named argument, one<- or
two<- ?  Or a third alternative that is better than both?
Comments and critiques welcome.

Cheers,
Bert