- print_r: documentation ( source)
<?php
$pq = new SplPriorityQueue();
//insert method inserts an element in the queue by shifting it up
$pq->insert('A', 3);
$pq->insert('B', 6);
$pq->insert('C', -1);
$pq->insert('D', 2);
//count the elements
echo "count ->" . $pq->count() . "<br />";
//Sets the mode of extraction (EXTR_DATA, EXTR_PRIORITY, EXTR_BOTH)
$pq->setExtractFlags(SplPriorityQueue::EXTR_BOTH);
//go at the node from the top of the queue
$pq->top();
//iterate the queue (by priority) and display each element
while ($pq->valid()) {
print_r($pq->current());
echo "<br />";
$pq->next();
}