Use purrr::map*() to assign a nested list element to another nested list-CodePudding

I have two lists:

listA <- list(group1 = tibble(names = LETTERS[1:5],
                              names_num = 1:5),
              group2 = tibble(names = LETTERS[11:13],
                              names_num = 1:3))
  
listB <- list(group1 = list(labels = NULL,
                            order = 5:1),
              group2 = list(labels = NULL,
                            order = 3:1))

My goal is to modify listB$groupX$labels by inserting the names vector from listA for each group, and in the order specified by listB$groupX$order. The desired output would look like this:

> listB_mod
$group1
$group1$labels
[1] "E" "D" "C" "B" "A"
$group1$order
[1] 5 4 3 2 1

$group2
$group2$labels
[1] "M" "L" "K"
$group2$order
[1] 3 2 1

Is there a way to achieve this, preferably using the purrr::map() family?

Any hints much appreciated!

CodePudding user response：

Most of the logic is unrelated to ‘purrr’ functionality but of course you can use map2 to apply the logic to all pairwise items in the two lists:

listB_mod = map2(
    listA, listB,
    ~ list(labels = .x$names[match(.x$names_num, .y$order)], order = .y$order)
)