search
HomeBackend DevelopmentPHP Tutorial这个正则中的x7f-xff是什么意思

看到一个源码中写的正则里
/\/i

中的 \x7f-xff代表什么意思


回复讨论(解决方案)

\x7f-\xff表示ASCII字符从127到255,其中\为转义。

这里为什么要从127到255这个范围取值呢?不好意思,再深入的问一下。

echo bin2hex('为什么'); //得 ceaacab2c3b4

echo "\xce\xaa\xca\xb2\xc3\xb4"; //得 为什么


这里为什么要从127到255这个范围取值呢?不好意思,再深入的问一下。

可能是IP地址分类吧
A:首位为0;1.0.0.0~126.0.0.0;主机号24位
B:前两位为10;128.1.0.0~191.255.0.0;主机号16位
C:前三位为110;192.0.1.0~223.255.255.0;主机号8位
D:前四位为1110;224.0.0.0~239.255.255.255 
E:前四位为1111;240.0.0.0~255.255.255.254

!!!这个和IP有什么关系!!!

在中括号中除了中括号本身或连接符表示范围的时候,其他情况都不是元字符。所以[\x7f-xff]代表\、x、7、f-x、f、f的字符组。

不好意思,昨天的回复是错误的,更正一下,元字符“\xn”用于匹配n,其中n为十六进制转义值,该值必须为确定的两个数字长。例如,“\x41”匹配“A”,“\x411”则等价于“A1”。而连接符“-”在字符组(中括号内的字符串)内表示一个范围(如果不在开头)。值得注意的是,在字符组内部和外部,关于元字符的规定是不同的。

Statement
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
Working with Flash Session Data in LaravelWorking with Flash Session Data in LaravelMar 12, 2025 pm 05:08 PM

Laravel simplifies handling temporary session data using its intuitive flash methods. This is perfect for displaying brief messages, alerts, or notifications within your application. Data persists only for the subsequent request by default: $request-

cURL in PHP: How to Use the PHP cURL Extension in REST APIscURL in PHP: How to Use the PHP cURL Extension in REST APIsMar 14, 2025 am 11:42 AM

The PHP Client URL (cURL) extension is a powerful tool for developers, enabling seamless interaction with remote servers and REST APIs. By leveraging libcurl, a well-respected multi-protocol file transfer library, PHP cURL facilitates efficient execution of various network protocols, including HTTP, HTTPS, and FTP. This extension offers granular control over HTTP requests, supports multiple concurrent operations, and provides built-in security features.

Simplified HTTP Response Mocking in Laravel TestsSimplified HTTP Response Mocking in Laravel TestsMar 12, 2025 pm 05:09 PM

Laravel provides concise HTTP response simulation syntax, simplifying HTTP interaction testing. This approach significantly reduces code redundancy while making your test simulation more intuitive. The basic implementation provides a variety of response type shortcuts: use Illuminate\Support\Facades\Http; Http::fake([ 'google.com' => 'Hello World', 'github.com' => ['foo' => 'bar'], 'forge.laravel.com' =>

12 Best PHP Chat Scripts on CodeCanyon12 Best PHP Chat Scripts on CodeCanyonMar 13, 2025 pm 12:08 PM

Do you want to provide real-time, instant solutions to your customers' most pressing problems? Live chat lets you have real-time conversations with customers and resolve their problems instantly. It allows you to provide faster service to your custom

PHP Logging: Best Practices for PHP Log AnalysisPHP Logging: Best Practices for PHP Log AnalysisMar 10, 2025 pm 02:32 PM

PHP logging is essential for monitoring and debugging web applications, as well as capturing critical events, errors, and runtime behavior. It provides valuable insights into system performance, helps identify issues, and supports faster troubleshoot

Explain the concept of late static binding in PHP.Explain the concept of late static binding in PHP.Mar 21, 2025 pm 01:33 PM

Article discusses late static binding (LSB) in PHP, introduced in PHP 5.3, allowing runtime resolution of static method calls for more flexible inheritance.Main issue: LSB vs. traditional polymorphism; LSB's practical applications and potential perfo

HTTP Method Verification in LaravelHTTP Method Verification in LaravelMar 05, 2025 pm 04:14 PM

Laravel simplifies HTTP verb handling in incoming requests, streamlining diverse operation management within your applications. The method() and isMethod() methods efficiently identify and validate request types. This feature is crucial for building

Discover File Downloads in Laravel with Storage::downloadDiscover File Downloads in Laravel with Storage::downloadMar 06, 2025 am 02:22 AM

The Storage::download method of the Laravel framework provides a concise API for safely handling file downloads while managing abstractions of file storage. Here is an example of using Storage::download() in the example controller:

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

AI Hentai Generator

AI Hentai Generator

Generate AI Hentai for free.

Hot Article

Hot Tools

MantisBT

MantisBT

Mantis is an easy-to-deploy web-based defect tracking tool designed to aid in product defect tracking. It requires PHP, MySQL and a web server. Check out our demo and hosting services.

Atom editor mac version download

Atom editor mac version download

The most popular open source editor

Dreamweaver Mac version

Dreamweaver Mac version

Visual web development tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 English version

SublimeText3 English version

Recommended: Win version, supports code prompts!