How to get a competent tree menu from a multi-level php array?

Question

PHP

How to properly display such an array in php as a tree?

array(2) {
   ["docs"]=>
   array(2) {
     [1]=>
    array(2) {
      [11]=>
      array(1) {
        [111]=>
        array(1) {
          [1111]=>
          array(1) {
            [11111]=>
            array(0) {
            }
          }
        }
      }
      [12]=>
      array(0) {
      }
    }
    [2]=>
    array(0) {
    }
  }
  ["photos"]=>
  array(0) {
  }
}

Answer 1

Answer 2

study recursions