略微加速

PHP官方手册 - 互联网笔记

PHP - Manual: SplPriorityQueue

2024-11-15

The SplPriorityQueue class

(PHP 5 >= 5.3.0, PHP 7, PHP 8)

简介

The SplPriorityQueue class provides the main functionalities of a prioritized queue, implemented using a max heap.

注意: The order of elements with identical priority is undefined. It may differ from the order in which they have been inserted.

类摘要

class SplPriorityQueue implements Iterator, Countable {
/* 方法 */
public compare(mixed $priority1, mixed $priority2): int
public count(): int
public current(): mixed
public extract(): mixed
public getExtractFlags(): int
public insert(mixed $value, mixed $priority): bool
public isCorrupted(): bool
public isEmpty(): bool
public key(): int
public next(): void
public recoverFromCorruption(): bool
public rewind(): void
public setExtractFlags(int $flags): int
public top(): mixed
public valid(): bool
}

目录

add a noteadd a note

User Contributed Notes 4 notes

up
21
rajatn at rediff dot co dot in
11 years ago
quick implementation of SPL Priority Queue:

<?php

class PQtest extends SplPriorityQueue
{
    public function compare($priority1, $priority2)
    {
        if ($priority1 === $priority2) return 0;
        return $priority1 < $priority2 ? -1 : 1;
    }
}

$objPQ = new PQtest();

$objPQ->insert('A',3);
$objPQ->insert('B',6);
$objPQ->insert('C',1);
$objPQ->insert('D',2);

echo "COUNT->".$objPQ->count()."<BR>";

//mode of extraction
$objPQ->setExtractFlags(PQtest::EXTR_BOTH);

//Go to TOP
$objPQ->top();

while($objPQ->valid()){
    print_r($objPQ->current());
    echo "<BR>";
    $objPQ->next();
}

?>

output:

COUNT->4
Array ( [data] => B [priority] => 6 )
Array ( [data] => A [priority] => 3 )
Array ( [data] => D [priority] => 2 )
Array ( [data] => C [priority] => 1 )
up
14
doublecompile at gmail dot com
6 years ago
I've used the SplPriorityQueue to determine an HTTP client's preferred MIME types.

<?php
$queue = new \SplPriorityQueue();
foreach (preg_split('#,\s*#', $_SERVER['HTTP_ACCEPT']) as $accept) {
    $split = preg_split('#;\s*q=#', $accept, 2);
    $queue->insert($split[0], isset($split[1]) ? (float)$split[1] : 1.0);
}
foreach ($queue as $mime) {
    echo $mime, PHP_EOL;
}
?>

My browser sends:
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8

And this script outputs:
text/html
application/xhtml+xml
application/xml
*/*

A better example:
Accept: text/html, application/xml,text/css;q=0.4,text/plain; q=0.9, application/json;q=0.8

And this script outputs:
text/html
application/xml
text/plain
application/json
text/css
up
9
Hayley Watson
8 years ago
For a heap-based priority queue to be at its most effective, the "priority" should be something that can take on a wide range of values (lengths, timestamps, populations). It optimises the tasks of searching the queue for the appropriate place to insert an item (and inserting it); and removing the first item in the list.

Items may potentially be inserted into the queue wherever two adjacent items have different priorities. The heap structure is an efficient way of indexing such insertion points when there are many of them distributed throughout the list.

If you have a sharply-limited enumeration of possible priority values, then there are very few insertion possible insertion points - one for each priority value. In that situation, one can make the insertion points explicit (and thus eliminate the need to maintain a heap indexing them) by implementing your priority queue as a list of simple queues from which you draw successive items from the highest-priority nonempty queue.
up
10
lsroudi at gmail dot com
8 years ago
<?php

/**
* Description of PriorityQueue
*
* (c) lsroudi http://lsroudi.com/ <lsroudi@gmail.com>
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
interface PriorityLoggerInterface {

    public function insert($value, $priority);
}

class PriorityLogger extends SplPriorityQueue implements PriorityLoggerInterface {
   
}

class Logger {

    const ERROR = 3;
    const NOTICE = 1;
    const WARNING = 2;

    private $priorityLogger;

    public function __construct(PriorityLoggerInterface $priorityLogger)
    {
        $this->priorityLogger = $priorityLogger;
    }

    public function addMessage($value, $priority)
    {
        $this->priorityLogger->insert($value, $priority);
    }

    public function getPriorityLogger()
    {
        return $this->priorityLogger;
    }

}

$priorityLogger = new PriorityLogger();

$logger = new Logger($priorityLogger);
$logger->addMessage('Message with notice type', Logger::NOTICE);
$logger->addMessage('Message with warning type', Logger::WARNING);
$logger->addMessage('Message with error type', Logger::ERROR);

$priorityLoggerQueue = $logger->getPriorityLogger();

foreach ($priorityLoggerQueue as $queue){
    print $queue . PHP_EOL;
}

//Résultat
//Message with error type
//Message with warning type
//Message with notice type
?>
add a noteadd a note

官方地址：https://www.php.net/manual/en/class.splpriorityqueue.php

有任何技术问题请点击这里 网站运营推广招聘
IT PHP 编程语言 Linux 开发编程 科技 Elasticsearch HTML/CSS/XML 网络 JAVA NoSQL 数据库 面试 C/C++ Golang Git 算法 操作系统 正则表达式 Redis 互联网 MySql JavaScript 运维 软件 国际 架构设计 Mac OS TCP/IP Excel Vim Windows Socket Oracle VR MongoDB Python 运营 MemCache 商业 硬件 电子 娱乐 设计 nginx 摄影 游戏 WordPress HTTP 团建 数码电器
冷却塔厂家 广告
-- --
php7 安装fileinfo扩展 preg_split — 通过一个正则表达式分隔字符串 php位值,解决 PHP 中 usort 在值相同时改变原始位置的问题 [PHP] inet_pton/inet_ntop IP地址转换函数 array_multisort() 多字段排序 PHPMailer设置utf8 PHPMailer字符集CharSet ADORecordSet对象 adodb手册 PHP 8.1 [鸟哥]PHP_INT_MIN 和 -9223372036854775808 opcache预加载 Composer的Packagist资源 mysql面试题 [鸟哥]PHP FFI详解 - 一种全新的PHP扩展方式 PHP7添加redis扩展 Packagist / Composer 中国全量镜像 PHP获取指定函数定义在哪个文件中及行号 PHP mkdir()写出来的权限与mode值不符合 常用的php ADODB使用方法集锦 php设置cookie为httponly防止xss攻击
联系我们 半月雨文化 可降解耗材网 蓝云环保 78免费小説 上海网站seo优化 工程造价 币安app官网下载 seo查询
北京半月雨文化科技有限公司.版权所有 京ICP备12026184号-3