Online PHP editor | output for mR3oG

@ 2015-08-01T20:47:22Z

<?php

$items = array(
        (object) array('id' => 1, 'parent_id' => 0),
        (object) array('id' => 2, 'parent_id' => 1),
        (object) array('id' => 3,  'parent_id' => 1),
        (object) array('id' => 4, 'parent_id' => 2),
        (object) array('id' => 5, 'parent_id' => 4),
        (object) array('id' => 6,  'parent_id' => 0),
);

function buildTree($items) {

    $childs = array();

    foreach($items as $item)
        $childs[$item->parent_id][] = $item;

    foreach($items as $item) if (isset($childs[$item->id]))
        $item->childs = $childs[$item->id];

    return $childs[0];
}

$tree = buildTree($items);
print_r($tree);

Output for 5.0.0 - 5.0.5, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.24 - 5.5.35, 5.6.8 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.7, 7.2.29 - 7.2.33, 7.3.16 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6: Array ( [0] => stdClass Object ( [id] => 1 [parent_id] => 0 [childs] => Array ( [0] => stdClass Object ( [id] => 2 [parent_id] => 1 [childs] => Array ( [0] => stdClass Object ( [id] => 4 [parent_id] => 2 [childs] => Array ( [0] => stdClass Object ( [id] => 5 [parent_id] => 4 ) ) ) ) ) [1] => stdClass Object ( [id] => 3 [parent_id] => 1 ) ) ) [1] => stdClass Object ( [id] => 6 [parent_id] => 0 ) )
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9: Array ( [0] => stdClass Object ( [id] => 1 [parent_id] => 0 ) [1] => stdClass Object ( [id] => 6 [parent_id] => 0 ) )

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