Hi Ben,
How about something like this:
f <- function(x, y = NULL) {
if (is.null(y))
y <- x
x + y
}
> f(3, 4)
[1] 7
> f(3)
[1] 6
Regards,
Marc Schwartz
> On Jun 20, 2020, at 7:15 AM, Benjamin Tyner <bty...@gmail.com> wrote:
>
> Greetings,
>
> Occasionally, I desire to call a function with one argument set to equal to
> another. Here is a toy example:
>
> f <- function(x, y) {
>
> x + y
> }
>
> f(x = 3, y = x) # Error in f(x = 3, y = x) : object 'x' not found
>
> So far, the most concise way I found to accomplish this is:
>
> f(x = 3, y = local(sys.frame(1)$x)) # evaluates to 6
>
> but I dislike this solution because local() creates a new environment. Surely
> there must be a better way?
>
> Note: I'm not interested in solutions that require modifying or currying f.
>
> Regards,
> Ben
>
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