[R] Extracting specific arguments from "..."

Bert Gunter bgunter@4567 @end|ng |rom gm@||@com
Sun Jan 5 20:17:02 CET 2025


Thanks, Iris.
That is what I suspected, but it wasn't clear to me from the docs.

Best,
Bert

On Sun, Jan 5, 2025 at 10:16 AM Iris Simmons <ikwsimmo using gmail.com> wrote:
>
> 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 using 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
>>
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