How to check if any arguments were passed via "..." (ellipsis) in R? Is missing(...) valid?
Here's an alternative that will throw an error if you try to pass in a non-existent object.
test2 <- function(...) if(length(list(...))) FALSE else TRUE
test2()
#[1] TRUE
test2(something)
#Error in test2(something) : object 'something' not found
test2(1)
#[1] FALSE
I think match.call is what you need:
test <- function(...) {match.call(expand.dots = FALSE)}
> test()
test()
> test(x=3,y=2,z=5)
test(... = list(x = 3, y = 2, z = 5))
It will give you every time the values passed in the ellipsis, or it will be blank if you won't pass any.
Hope that helps!