Online PHP editor | refs for P8L79

<?php $arr = array ( 'igive' => array ( 0 => array ( 'name' => 'Alex', 'shop_name' => 'Shop1', 'rights' => 'admin', 'who_use' => '', 'user_id' => '765754346', ), 1 => array ( 'name' => 'Dmitry', 'shop_name' => 'Shop2', 'rights' => 'manager', 'who_use' => '', 'user_id' => '123456789', ), ), 'giventome' => array ( ), ); /*How can i set value (1, for example) for a key 'who_use' where 'user_id' = 765754346?*/ $user_id = '765754346'; array_walk($arr['igive'], function($v, $k) use (&$arr, $user_id){ ($arr['igive'][$k]['user_id'] == $user_id) ? ($arr['igive'][$k]['who_use'] = 1) : ''; }); print_r($arr);