Creating a function in R with variable number of arguments,

Question

When creating a function in R, we usually specify the number of argument like

function(x,y){
}

That means it takes only two arguments. But when the numbers of arguments are not specified (For one case I have to use two arguments but another case I have to use three or more arguments) how can we handle this issue? I am pretty new to programming so example will be greatly appreciated.

Answer 1

d <- function(...){
    x <- list(...) # THIS WILL BE A LIST STORING EVERYTHING:
    sum(...)       # Example of inbuilt function
}

d(1,2,3,4,5)

[1] 15 

Answer 2

You can use ... to specify an additional number of arguments. For example:

myfun <- function(x, ...) {
    for(i in list(...)) {
        print(x * i)
    }
}

> myfun(4, 3, 1)
[1] 12
[1] 4
> myfun(4, 9, 1, 0, 12)
[1] 36
[1] 4
[1] 0
[1] 48
> myfun(4)