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Iterator::key

(PHP 5 >= 5.0.0, PHP 7)

Iterator::key返回当前元素的键

说明

abstract public scalar Iterator::key ( void )

返回当前元素的键。

参数

此函数没有参数。

返回值

成功返回标量,失败则返回 NULL

错误/异常

失败时分发 E_NOTICE 级错误。

User Contributed Notes

michaelgranados at gmail dot com 27-Jun-2013 12:46
Since PHP 5.5.X foreach can accept non scalar items. So the return can be anything ;)
Lszl Lajos Jnszky 14-Mar-2012 09:34
And converts everything to integer except string, so in php the post process could be:

    public function key() {
        $yourKey = $this->createYourKey();
        if (is_object($yourKey) || is_array($yourKey))
            throw new Exception('Array and Object not allowed.');
        elseif (is_string($yourKey))
            return $yourKey;
        else
            return (int) $yourKey;
    }

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