« SplPriorityQueue::setExtractFlags SplPriorityQueue::valid » PHP Manual SplPriorityQueue Peeks at the node from the top of the queue SplPriorityQueue::top (PHP 5 >= 5.3.0, PHP 7) SplPriorityQueue::top — Peeks at the node from the top of the queue 说明 public SplPriorityQueue::top ( void ) : mixed 参数 此函数没有参数。 返回值 The value or priority (or both) of the top node, depending on the extract flag.