R: Find object by name in deeply nested list

Here's a function that will return the first match if found

find_name <- function(haystack, needle) {
 if (hasName(haystack, needle)) {
   haystack[[needle]]
 } else if (is.list(haystack)) {
   for (obj in haystack) {
     ret <- Recall(obj, needle)
     if (!is.null(ret)) return(ret)
   }
 } else {
   NULL
 }
}

find_name(my_list, "XY01")

We avoid lapply so the loop can break early if found.

The list pruning is really a separate issue. Better to attack that with a different function. This should work

list_prune <- function(list, depth=1) {
  if (!is.list(list)) return(list)
  if (depth>1) {
    lapply(list, list_prune, depth = depth-1)
  } else  {
    Filter(function(x) !is.list(x), list)
  }
}

Then you could do

list_prune(find_name(my_list, "XY01"), 1)

or with pipes

find_name(my_list, "XY01") %>% list_prune(1)