Hullo,
If I've got a function
foo <- function(list, name)
where I would want
foo(list, c("a", "b", "c"))
to return
list[[a]][[b]][[c]]
and also fail gracefully if list[[a]][[b]][[c]] doesn't exist,
How do I accomplish this ideally in base R?
We could use pluck
foo <- function(list, name) {
purrr::pluck(list, !!! name)
}
-testing
> lst1 <- list(a = list(b = list(c = 1:2)), b = list(d = list(e = 1:5)))
> foo(lst1, c("a", "b", "c"))
[1] 1 2
Or simply in base R
foo <- function(list, name) {
list[[name]]
}
> foo(lst1, c("a", "b", "c"))
[1] 1 2
?"!!!". Updated the base R option[[ function actually just works exactly like what I wanted. I'd assumed it didn't work that way. Note that the base R solution doesn't work with a mix of numeric indexes and names, i.e. foo(lst1, c(1, "b", "c") doesnt work while pluck doesc converts it to a single type