Subset a list without knowing its structure in r

Question

I have a list in R:

my_list <- list(a = 1, b = 2, c = list(d = 4, e = 5))

Suppose I don't know the structure of the list, but I know that somewhere in this list, there is an element named d, nested or not. I would like to:

1. Subset that list element, without knowing the structure of the master list that contains it
2. Know the name of its parent list (i.e. element c)

Is there an easy method / package that can solve this seemingly simple problem?

Answer 1

I'm implementing the suggestion by @r2evans. I'm sure this can be improved:

getParentChild <- function(lst, myN) {
    myFun <- function(lst, myN) {
        test <- which(names(lst) == myN)
        if (length(test) > 0)
            return(lst[test])

        lapply(lst, function(x) {
            if (is.list(x))
                myFun(x, myN)
        })
    }

    temp <- myFun(lst, myN)
    temp[!sapply(temp, function(x) is.null(unlist(x)))]
}

getParentChild(my_list, "d")
$c
$c$d
[1] 4

Here is a more complicate example that illustrates how getParentChild shows lineage when there are multiple children/grandchildren.

exotic_list <- list(a = 1, b = 2, c = list(d = 4, e = 5), f = list(g = 6, h = list(k = 7, j = 8)), l = list(m = 6, n = list(o = 7, p = 8)), q = list(r = 5, s = 11), t = 12)

getParentChild(exotic_list, "n")
$l
$l$n
$l$n$o
[1] 7

$l$n$p
[1] 8