« SplHeap::rewind SplHeap::valid » PHP Manual SplHeap Peeks at the node from the top of the heap SplHeap::top (PHP 5 >= 5.3.0, PHP 7) SplHeap::top — Peeks at the node from the top of the heap 说明 public SplHeap::top ( void ) : mixed 参数 此函数没有参数。 返回值 The value of the node on the top. 错误/异常 Throws RuntimeException when the data-structure is empty.