Can I remove an element in … (dot-dot-dot) and pass it on?

Question

Is it possible to remove an element from ... and pass ... onto other functions? My first two attempts failed:

parent = function(...)
{

   a = list(...)
            


        

Answer 1

One way to manipulate these things is to wrap the child function inside parent, and use a definition that puts any arguments you don't want passing on to child after the ... argument. For example:

parent <- function(...) {
    localChild <- function(..., toRemove) child(...)
    localChild(...)
}
child <- function(a) {
    a + 10
}

> parent(a = 1, toRemove = 10)
[1] 11

Another way is to use do.call():

parent2 <- function(...) {
    a <- list(...)
    a$toRemove <- NULL
    do.call(child2, a)
}
child2 <- function(b) {
    b + 10
}
> parent2(b = 1, toRemove = 10)
[1] 11

Depending on your actual use case, the do.call() is perhaps closest to what you intended with your Question.