« IteratorIterator::getInnerIterator IteratorIterator::next » PHP Manual IteratorIterator Get the key of the current element IteratorIterator::key (PHP 5 >= 5.1.0, PHP 7) IteratorIterator::key — Get the key of the current element 说明 public IteratorIterator::key ( void ) : mixed Get the key of the current element. 参数 此函数没有参数。 返回值 The key of the current element. 参见 IteratorIterator::current() - Get the current value