Hi,
is there an easy, robust, and/or recommended way to distinguish a
missing argument from an empty argument as in:
foo <- function(i, j){
print(missing(j))
print(nargs())
}
foo(i) # TRUE, 1
foo(i,) # TRUE, 2
I know I can work around with nargs, the list of arguments and the names
of the passed arguments, but I wish there is something already in place
for this.
This is specially important for '['-like methods where x[i,] is not the
same as x[i].
What I am looking for is a function that tells me if an argument has
actually been passed empty:
foo <- function(i, j, k){
print( empty.arg(j) )
print(nargs())
}
would result in:
foo(i) # FALSE, 1
foo(i, ) # TRUE, 2
foo(i, j) # FALSE, 2
foo(i, k=2) # FALSE, 2
foo(i, k=2, ) # TRUE, 3
Thank you for any help or pointer.
Bests,
Renaud
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