SplHeap::extract()

(PHP 5 >= 5.3.0, PHP 7)

Extracts a node from top of the heap and sift up

说明

publicSplHeap::extract(void) : mixed

参数

此函数没有参数。

返回值

The value of the extracted node.

错误／异常

Throws RuntimeException when the data-structure is empty.

<?php
$heap = new SplMaxHeap(); # Ascending order
$heap->insert('E');
$heap->insert('B');
$heap->insert('D');
$heap->insert('A');
$heap->insert('C');
echo $heap->extract(), PHP_EOL; # E
echo $heap->extract(), PHP_EOL; # D
$heap = new SplMinHeap(); # Descending order
$heap->insert('E');
$heap->insert('B');
$heap->insert('D');
$heap->insert('A');
$heap->insert('C');
print PHP_EOL;
echo $heap->extract(), PHP_EOL; # A
echo $heap->extract(), PHP_EOL; # B
?>