无循环的数组结构重排

Question

I have an array like mentioned below, which I want to rearrange without using loop:

Array
(
    [0] => Array
        (
            [Books] => Array
                (
                    [id] => 4
                )

        )

    [1] => Array
        (
            [Books] => Array
                (
                    [id] => 3
                )

        )

    [2] => Array
        (
            [Books] => Array
                (
                    [id] => 2
                )

        )

    [3] => Array
        (
            [Books] => Array
                (
                    [id] => 1
                )

        )

)

I want an output like this:

Array(4,3,2,1)

Answer 1

I'm assuming you do not want to use for or foreach loops, but anything else that internally is or uses a loop is fine.

in this case, you can use array_map:

$result = array_map(function($item){
  return $item['books']['id'];
}, $currentArray);

OR

if you do not even want that:

$v1 = array_column($input, 'books');
$result = array_column($v1, 'id');