I have two functions nested in another function and I would like that the arguments declared in parent were passed to the child (only when the argument is relevant to the function).
# child function 1
child_f1 <- function(x1 = 1, x2 = 3) {
res <- x1^2 + 4 * x2
}
# child function 2
child_f2 <- function(z = 2) {
res <- z * 1.345
}
# parent function
parent_f <- function(y = 4, ...) {
res <- (child_f1(...) ^ y) + child_f2(...)
# print(res)
return(res)
}
Test below:
parent_f(y = 2, x1 = 2, x2 = 0, z = 3)
# Error in child_f1(...) (from #2) : unused argument (z = 3)
# Expected result:
(((2)^2 + 4*(0)) ^ (2)) + (3) * 1.345
[1] 20.04
How do I tell child_f1 that has to use only x1 and x2 (if available, otherwise use default value) and child_f2 that has to use only z(if available, otherwise use default value)?
I would like to stick with the usage of ... rather than re-write a parent_f() with all the possible parameters declared.
Add ... to each child to slurp up the unused arguments. parent_f is unchanged.
child_f1 <- function(x1 = 1, x2 = 3, ...) {
res <- x1^2 + 4 * x2
}
child_f2 <- function(z = 2, ...) {
res <- z * 1.345
}
parent_f(y = 2, x1 = 2, x2 = 0, z = 3)
## [1] 20.035
If you can't modify the children or the parent then use this:
child_f1_orig <- child_f1
child_f1 <- function(x1 = 1, x2 = 3, ...) child_f1_orig(x1 = x1, x2 = x2)
child_f2_orig <- child_f2
child_f2 <- function(z = 2, ...) child_f2_orig(z = z)
parent_f(y = 2, x1 = 2, x2 = 0, z = 3)
## [1] 20.035