- var_dump: documentation ( source)
<?php
$obj = array();
var_dump(isset($obj['name']));
unset($obj['name']);
$obj = new ArrayObject(array(), ArrayObject::ARRAY_AS_PROPS | ArrayObject::STD_PROP_LIST);
var_dump(isset($obj['name']));
unset($obj['name']);
$obj = new ArrayObject;
var_dump(isset($obj['name']));
unset($obj['name']);