Backend Development
PHP Tutorial
Detailed explanation of the queue principle in PHP and the graphic code for writing files
Detailed explanation of the queue principle in PHP and the graphic code for writing files
The examples in this article describe the PHP queue principle and queue-based file writing cases. Share it with everyone for your reference, the details are as follows:
The queue is a linear table, based on the first in first out principle:
Joining the team:
Leaving the team:
# #PHP implementation queue: The first element is the head of the queue, and the last element is the tail of the queue
<?php /** * 队列就是这么简单 * * @link */ $array = array('PHP', 'JAVA'); array_push($array, 'PYTHON'); //入队列 array_shift($array); //出队列
What is a double-ended queue (or two-way queue) Deque, the full name is double -ended queue?
That is, elements can be entered or dequeued at any part of the queue. If we call these methods insertLeft() and insertRight(), as well as removeLeft() and removeRight(). If calling the insertLeft() and removeLeft() methods is strictly prohibited (or the operation of the right segment is disabled), the double-ended queue functions like a stack. It is forbidden to call insertLeft() and removeRight() (or another pair of methods on the contrary), and its function is the same as a queue. A deque is a versatile data structure compared to a stack or queue.PHP implements double-ended queue
<?php
class Deque
{
public $queue = array();
/**（尾部）入队 **/
public function addLast($value)
{
return array_push($this->queue,$value);
}
/**（尾部）出队**/
public function removeLast()
{
return array_pop($this->queue);
}
/**（头部）入队**/
public function addFirst($value)
{
return array_unshift($this->queue,$value);
}
/**（头部）出队**/
public function removeFirst()
{
return array_shift($this->queue);
}
/**清空队列**/
public function makeEmpty()
{
unset($this->queue);
}
/**获取列头**/
public function getFirst()
{
return reset($this->queue);
}
/** 获取列尾 **/
public function getLast()
{
return end($this->queue);
}
/** 获取长度 **/
public function getLength()
{
return count($this->queue);
}
}Purpose of queue:
Queue can be very good Process data transmission and storage asynchronously. When you frequently insert data into the database and submit data to search engines, you can use queues to insert data asynchronously. In addition, slower processing logic and processing logic with limited concurrency can also be placed in the background for processing through message queues, such as FLV video conversion, sending mobile phone text messages, sending emails, etc. Project CaseThere is a project here. Due to server permission issues, there is no way to install the queue program, and there are more than 300 concurrent users. The service provider The maximum number of connections to the database is 300. In order to solve this problem, a simple queue program was written. The code is as follows
Read queue code:<?php
set_time_limit(0);
$file_name3 = '3.txt';//这个地方是讲队列文件读出的内容写入文件，test中代替的是mysql数据库操作
$file3 = fopen($file_name3,'a');
while(true)
{
$c = FALSE;
$file_name = '1.txt';//队列文件
$file = fopen($file_name,'r');
if(!feof($f))
{
//获得第一条数据
$a = fgets($file);
if(!empty($a))
{
$c = TRUE;
fwrite($file3,$a);//这里可以改为数据库操作
}
}
fclose($file);
if($c)
{
//将文件的第一条数据删除
exec('sed -i \'1d\' /var/www/csv_sql/1.txt');
}
sleep(1);
if(time()>=strtotime('20160416150000'))
{
exit;
}
}
fclose($file3);Reading the file
Writing the queue program is relatively simple, just write the file
<?php
set_time_limit(0);
$file_name2 = '2.txt';//test中用来比对队列程序是否正常的
$file2 = fopen($file_name2,'a');
for($i=1;$i<11;$i++)
{
$file_name = '1.txt';//队列文件
$file = fopen($file_name,'a');//fopen的mode属性必须是a或a+
$str = $i.'--'.rand(100001,999999);
fwrite($file,$str."\n");
fwrite($file2,$str."\n");
sleep(1);
fclose($file);
}
fclose($file2);The above is the detailed content of Detailed explanation of the queue principle in PHP and the graphic code for writing files. For more information, please follow other related articles on the PHP Chinese website!
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
Clothoff.io
AI clothes remover
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
1668
14
1426
52
1329
25
1273
29
1256
24
PHP: A Key Language for Web Development
Apr 13, 2025 am 12:08 AM
PHP is a scripting language widely used on the server side, especially suitable for web development. 1.PHP can embed HTML, process HTTP requests and responses, and supports a variety of databases. 2.PHP is used to generate dynamic web content, process form data, access databases, etc., with strong community support and open source resources. 3. PHP is an interpreted language, and the execution process includes lexical analysis, grammatical analysis, compilation and execution. 4.PHP can be combined with MySQL for advanced applications such as user registration systems. 5. When debugging PHP, you can use functions such as error_reporting() and var_dump(). 6. Optimize PHP code to use caching mechanisms, optimize database queries and use built-in functions. 7
PHP vs. Python: Understanding the Differences
Apr 11, 2025 am 12:15 AM
PHP and Python each have their own advantages, and the choice should be based on project requirements. 1.PHP is suitable for web development, with simple syntax and high execution efficiency. 2. Python is suitable for data science and machine learning, with concise syntax and rich libraries.
PHP and Python: Comparing Two Popular Programming Languages
Apr 14, 2025 am 12:13 AM
PHP and Python each have their own advantages, and choose according to project requirements. 1.PHP is suitable for web development, especially for rapid development and maintenance of websites. 2. Python is suitable for data science, machine learning and artificial intelligence, with concise syntax and suitable for beginners.
PHP in Action: Real-World Examples and Applications
Apr 14, 2025 am 12:19 AM
PHP is widely used in e-commerce, content management systems and API development. 1) E-commerce: used for shopping cart function and payment processing. 2) Content management system: used for dynamic content generation and user management. 3) API development: used for RESTful API development and API security. Through performance optimization and best practices, the efficiency and maintainability of PHP applications are improved.
The Enduring Relevance of PHP: Is It Still Alive?
Apr 14, 2025 am 12:12 AM
PHP is still dynamic and still occupies an important position in the field of modern programming. 1) PHP's simplicity and powerful community support make it widely used in web development; 2) Its flexibility and stability make it outstanding in handling web forms, database operations and file processing; 3) PHP is constantly evolving and optimizing, suitable for beginners and experienced developers.
PHP vs. Other Languages: A Comparison
Apr 13, 2025 am 12:19 AM
PHP is suitable for web development, especially in rapid development and processing dynamic content, but is not good at data science and enterprise-level applications. Compared with Python, PHP has more advantages in web development, but is not as good as Python in the field of data science; compared with Java, PHP performs worse in enterprise-level applications, but is more flexible in web development; compared with JavaScript, PHP is more concise in back-end development, but is not as good as JavaScript in front-end development.
PHP and Python: Different Paradigms Explained
Apr 18, 2025 am 12:26 AM
PHP is mainly procedural programming, but also supports object-oriented programming (OOP); Python supports a variety of paradigms, including OOP, functional and procedural programming. PHP is suitable for web development, and Python is suitable for a variety of applications such as data analysis and machine learning.
PHP and Python: Code Examples and Comparison
Apr 15, 2025 am 12:07 AM
PHP and Python have their own advantages and disadvantages, and the choice depends on project needs and personal preferences. 1.PHP is suitable for rapid development and maintenance of large-scale web applications. 2. Python dominates the field of data science and machine learning.
