SplPriorityQueue::compare

(PHP 5 >= 5.3.0)

SplPriorityQueue::compare — Compare priorities in order to place elements correctly in the heap while sifting up.

说明

int SplPriorityQueue::compare ( mixed $priority1 , mixed $priority2 )

Compare priority1 with priority2.

参数

priority1: The priority of the first node being compared.
priority2: The priority of the second node being compared.

返回值

Result of the comparison, positive integer if priority1 is greater than priority2, 0 if they are equal, negative integer otherwise.

Note:
Multiple elements with the same priority will get dequeued in no particular order.

PHP手册 - N: Compare priorities in order to place elements correctly in the heap while sifting up.

用户评论:

Anonymous (11-Oct-2009 12:51)

At this time, the documentation sais "Note: Multiple elements with the same priority will get dequeued in no particular order." If you need elements of equal priority to maintain insertion order, you can use something like: <?php class StablePriorityQueue extends SplPriorityQueue { protected $serial = PHP_INT_MAX; public function insert($value, $priority) { parent::insert($value, array($priority, $this->serial--)); } } ?>