Online PHP editor | refs for n694Z

<?php class NameObj { public $name; function __construct($name){ $this->name = $name; } } class IdObj{ public $id; function __construct($id){ $this->id = $id; } } $idArray = array( new IdObj(1), new IdObj(2), new IdObj(3) ); $nameArray = array( new NameObj('1 - Object 1 Name'), new NameObj('2 - Object 2 Name') ); function custom_diff($oId, $oName) { $one = $oId instanceof IdObj?$oId->id:explode(' - ', $oId->name)[0]; $two = $oName instanceof NameObj?explode(' - ', $oName->name)[0]:$oName->id; return $one-$two; } $missing_objects = array_udiff($idArray, $nameArray, 'custom_diff'); print_r($missing_objects);