Summary of practical regular expressions in PHP
这篇文章主要介绍了PHP经典实用正则表达式,结合具体实例总结分析了php基于正则实现验证、查找、匹配等相关操作技巧,需要的朋友可以参考下
对于开发人员来说，正则表达式是一个非常有用的功能，它提供了 查找，匹配，替换 句子，单词，或者其他格式的字符串。这里介绍了几个超实用的php正则表达式，需要的朋友可以参考下。
1. 验证域名检验一个字符串是否是个有效域名
<?php
$url = "https://www.baidu.com";
if (preg_match('/^(http|https|ftp):\/\/([A-Z0-9][A-Z0-9_-]*(?:.[A-Z0-9][A-Z0-9_-]*)+):?(d+)?\/?/i', $url)) {
echo "Your url is ok.";
} else {
echo "Wrong url.";
}2. 从一个字符串中 突出某个单词
这是一个非常有用的在一个字符串中匹配出某个单词 并且突出它，非常有效的搜索结果
<?php
$text = "Sample sentence from KomunitasWeb, regex has become popular in web programming. Now we learn regex. According to wikipedia, Regular expressions (abbreviated as regex or
regexp, with plural forms regexes, regexps, or regexen) are written in a formal language that can be interpreted by a regular expression processor";
$text = preg_replace("/(regex)/i", '<span style="background:#5fc9f6">1</span>', $text);
echo $text;function get_the_title(){
return 'Save the search.php file and open style.css. Append the following line to it: ';
}
$s = 'and php';
$title = get_the_title();
$keys= explode(" ",$s);
$title = preg_replace('/('.implode('|', $keys) .')/iu',
'<strong>\0</strong>',
$title);
echo $title;3. 从HTML文档中获得全部图片
如果你曾经希望去获得某个网页上的全部图片，这段代码就是你需要的，你可以轻松的建立一个图片下载机器人
<?php
$images = array();
$data = file_get_contents('https://www.baidu.com');
preg_match_all('/(img|src)=("|\')[^"\'>]+/i', $data, $media);
unset($data);
$data=preg_replace('/(img|src)("|\'|="|=\')(.*)/i',"$3",$media[0]);
foreach($data as $url)
{
$info = pathinfo($url);
if (isset($info['extension']))
{
if (($info['extension'] == 'jpg') ||
($info['extension'] == 'jpeg') ||
($info['extension'] == 'gif') ||
($info['extension'] == 'png'))
array_push($images, $url);
}
}
var_dump($images);4. 匹配一个XML或者HTML标签
这个简单的函数有两个参数：第一个是你要匹配的标签，第二个是包含XML或HTML的变量，再强调下，这个真的很强大
<?php
function get_tag( $tag, $xml ) {
$tag = preg_quote($tag);
output($tag);
preg_match_all('/<'.$tag.'[^>]*>(.*?)<\/'.$tag.'>./',
$xml,
$matches,
PREG_PATTERN_ORDER
);
return $matches[1];
}
$xml = '<span>bb<a>bbb</a><a>ccc</a></span><span>bb<a>aa</a><p><a>ddd</a></p></span>';
$tag = 'a';
$return = get_tag($tag, $xml);
var_dump($return);
/*
array(2) {
[0]=>
array(3) {
[0]=>
string(11) "bbb<"
[1]=>
string(10) "aa<"
[2]=>
string(11) "ddd<"
}
[1]=>
array(3) {
[0]=>
string(3) "bbb"
[1]=>
string(2) "aa"
[2]=>
string(3) "ddd"
}
}
array(3) {
[0]=>
string(3) "bbb"
[1]=>
string(2) "aa"
[2]=>
string(3) "ddd"
}
*/以上就是本文的全部内容，希望对大家的学习有所帮助。
相关推荐：
PHP基础教程(php入门基础教程)一些code代码_php基础
The above is the detailed content of Summary of practical regular expressions in PHP. 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
1428
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 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 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: 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.
