正则表达式测试
测试和调试正则表达式
使用方法
粘贴或输入内容
在输入区域输入您的文字、代码或数据。
选择选项
选取要应用的转换方式或格式。
复制结果
一键将输出结果复制到剪贴板。
为什么使用此工具
100% 免费
没有隐藏费用，没有付费等级——所有功能完全免费。
无需安装
完全在浏览器中运行。无需下载或安装任何软件。
隐私且安全
您的数据永远不会离开您的设备。不会上传至任何服务器。
支持移动设备
完全响应式设计——在手机、平板或桌面电脑上均可使用。
Regular Expressions: Pattern Matching Mastery
Key Takeaways
- Regular expressions provide powerful pattern matching for text validation, extraction, search, and transformation.
- Understanding regex quantifiers, character classes, groups, and lookaheads is essential for writing efficient patterns.
- All regex testing runs in your browser — your test data is never sent to any server.
Regular expressions (regex) are one of the most powerful tools in a developer's toolkit, enabling complex text pattern matching in a single expression. From validating email addresses and parsing log files to extracting data from unstructured text, regex is used across virtually every programming language and text processing tool. Mastering regex dramatically increases productivity in text-heavy development tasks.
Regular expressions are supported natively in over 30 programming languages and virtually every text editor.
Universal Support
Key Concepts
Character Classes and Quantifiers
Character classes ([a-z], \d, \w, \s) match categories of characters. Quantifiers (*, +, ?, {n,m}) control how many times a pattern repeats. Combining them creates powerful matchers.
Capture Groups and Backreferences
Parentheses create capture groups that extract matched substrings. Named groups (?<name>...) improve readability. Backreferences (\1 or \k<name>) match the same text again.
Lookaheads and Lookbehinds
Lookahead (?=...) and lookbehind (?<=...) assert that text exists before or after the match without including it in the result. Negative versions (?!...) and (?<!...) assert absence.
Greedy vs. Lazy Matching
By default, quantifiers are greedy (match as much as possible). Adding ? makes them lazy (match as little as possible). This distinction is critical for avoiding over-matching in complex patterns.
Pro Tips
Start with a simple pattern and incrementally add complexity — debugging a complex regex all at once is extremely difficult.
Use non-capturing groups (?:...) when you need grouping for alternation or quantifiers but do not need to capture the match.
Beware of catastrophic backtracking — nested quantifiers like (a+)+ on non-matching input can cause exponential processing time.
Use the 'u' flag in JavaScript regex for proper Unicode handling, especially when working with international text.
All regular expression testing is performed entirely in your browser using JavaScript's built-in RegExp engine. Your test strings and patterns are never transmitted to any server.