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

    up
    0
    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.
    ＋添加备注
    To Top