(PHP 5, PHP 7, PHP 8)
ArrayObject::offsetExists — Returns whether the requested index exists
keyThe index being checked.
true if the requested index exists, otherwise false
示例 #1 ArrayObject::offsetExists() example
<?php
$arrayobj = new ArrayObject(array('zero', 'one', 'example'=>'e.g.'));
var_dump($arrayobj->offsetExists(1));
var_dump($arrayobj->offsetExists('example'));
var_dump($arrayobj->offsetExists('notfound'));
?>
以上例程会输出：
bool(true) bool(true) bool(false)