ArrayObject::offsetExists

(PHP 5, PHP 7, PHP 8)

ArrayObject::offsetExists — Returns whether the requested index exists

说明

public ArrayObject::offsetExists(mixed $key): bool

参数

key: The index being checked.

返回值

true if the requested index exists, otherwise false

示例

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'));
?>

以上示例会输出：

bool(true)
bool(true)
bool(false)

改进此页面

了解如何改进此页面 • 提交拉取请求 • 报告一个错误

＋添加备注

用户贡献的备注 1 note

down

goran at extensionsforjoomla dot com ¶

17 years ago

In versions prior to PHP 5.2.2 offsetExists() would return false if index value is null.
<?php
// running PHP 5.2.1
$params = new ArrayObject(array('INT'=>null, 'STR'=> null, 'BOOL'=>null, 'LOB'=>null));
$test = $params->offsetExists('INT');
var_dump($test);
// result would be bool(false)
// running PHP 5.2.2
$params = new ArrayObject(array('INT'=>null, 'STR'=> null, 'BOOL'=>null, 'LOB'=>null));
$test = $params->offsetExists('INT');
var_dump($test);
// result would be bool(true)
?>
Both tests where made on Windows platform.