substitute() on arguments in ellipsis ("dot dot dot")?
On 12/08/2018 4:00 PM, Henrik Bengtsson wrote:
Hi. For any number of *known* arguments, we can do: one <- function(a) list(a = substitute(a)) two <- function(a, b) list(a = substitute(a), b = substitute(b)) and so on. But how do I achieve the same when I have: dots <- function(...) list(???) I want to implement this such that I can do:
exprs <- dots(1+2) str(exprs)
List of 1 $ : language 1 + 2 as well as:
exprs <- dots(1+2, "a", rnorm(3)) str(exprs)
List of 3 $ : language 1 + 2 $ : chr "a" $ : language rnorm(3) Is this possible to achieve using plain R code?
I think so. substitute(list(...)) gives you a single expression
containing a call to list() with the unevaluated arguments; you can
convert that to what you want using something like
dots <- function (...) {
exprs <- substitute(list(...))
as.list(exprs[-1])
}
Duncan Murdoch