How to return array for a recursive function using PHP?

Question

I have a Multi-dimensional array like this:

<pre>Array
(
    [0] => Array
        (
            [id] => 52a83521-0914-4264-8fd9-07d9c601692a
            [role_id] => 2
            [children] => Array
                (
                    [0] => Array
                        (
                            [id] => 54c1f5e4-b52c-4e17-b1bf-1f4616091b4e
                            [role_id] => 8
                            [children] => Array
                                (
                                    [0] => Array
                                        (
                                            [id] => 54c20aba-201c-40ce-b3df-22d516091b4e
                                            [role_id] => 9
                                        )

                                    [1] => Array
                                        (
                                            [id] => 54c20f4b-6e44-40ec-ae22-223a16091b4e
                                            [role_id] => 9
                                        )

                                )

                        )

                    [1] => Array
                        (
                            [id] => 54c1f8bb-ebac-466b-a83f-13a416091b4e
                            [role_id] => 8
                        )

                )

        )

)
</pre>

I need to get populate all role_id from this array in order. I tried using recursive function like this:

<?php
public function tree_check($tree){
  $tree_keys = $this->_recursion($tree);
  print_r($tree_keys);
}
public function _recursion($tree){
        foreach ($tree as $n => $v)
        {
            if(isset($v['role_id'])){
               $key_arr[] = $v['role_id']; 
            }
            if (is_array($v))
                $this->_recursion($v);

        }
        return $key_arr;
    }

I am expecting the following ouput:

<pre>
Array(
[0]=>2,
[1]=>8,
[2]=>9,
[3]=>9,
[4]=>8
)
</pre>

Here, I cannot achieve my expected output. The level of array may vary dynamically and that is why I have done it with recursive function.

How should I return the array from recursive function?

Since, I don't know how depth is my array, how can I find the last key value pair of array?

wat is current output?

Umair Ayub
– Umair Ayub

2015-01-26 18:30:48 +00:00
Commented Jan 26, 2015 at 18:30 — Umair Ayub
– Umair Ayub, Commented Jan 26, 2015 at 18:30

acontell · Accepted Answer · 2015-01-26 20:20:19Z

4

You can go through the elements using a RecursiveIteratorIterator:

function listRolesRecursive($myArray) {
    $res = array();
    $iterator = new RecursiveIteratorIterator(new RecursiveArrayIterator($myArray), RecursiveIteratorIterator::SELF_FIRST);
    foreach ($iterator as $k => $v) {
        if($k === "role_id") {
            $res[] = $v;
        }
    }
    return $res;
}

$res = listRolesRecursive($arr);
var_dump($res);

It should do the trick.

answered Jan 26, 2015 at 20:20

acontell

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