正则表达式

正则表达式速查表

完整的正则表达式语法参考，包含分类模式、量词、环视断言和实用示例。

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Common Patterns

/^[^\s@]+@[^\s@]+\.[^\s@]+$/

Example: [email protected]

Basic email validation

URL

/https?:\/\/[^\s]+/

Example: https://example.com/path

Match HTTP/HTTPS URLs

IPv4 Address

/\b(?:\d{1,3}\.){3}\d{1,3}\b/

Example: 192.168.1.1

IPv4 address pattern

Chinese Phone

/^1[3-9]\d{9}$/

Example: 13812345678

Mainland China mobile number

Date (YYYY-MM-DD)

/\d{4}-\d{2}-\d{2}/

Example: 2024-01-15

ISO date format

Character Classes

Pattern	Name	Example	Description
`.`	Any character	a.c → abc, aXc	Matches any single character except newline
`\d`	Digit	\d+ → 123	Matches any digit (0-9)
`\D`	Non-digit	\D+ → abc	Matches any non-digit character
`\w`	Word character	\w+ → hello_1	Matches letters, digits, underscore
`\W`	Non-word character	\W+ → !@#	Matches non-word characters
`\s`	Whitespace	a\sb → a b	Matches space, tab, newline
`\S`	Non-whitespace	\S+ → hello	Matches any non-whitespace character
`[abc]`	Character set	[aeiou] → a, e, i	Matches any character in set
`[^abc]`	Negated set	[^0-9] → a, b	Matches any character not in set
`[a-z]`	Character range	[a-z]+ → hello	Matches any character in range

Quantifiers

Pattern	Name	Example	Description
`*`	Zero or more	ab*c → ac, abc, abbc	Matches 0 or more of preceding
`+`	One or more	ab+c → abc, abbc	Matches 1 or more of preceding
`?`	Zero or one	ab?c → ac, abc	Matches 0 or 1 of preceding
`{n}`	Exact count	a{3} → aaa	Matches exactly n occurrences
`{n,}`	n or more	a{2,} → aa, aaa	Matches n or more occurrences
`{n,m}`	Between n and m	a{2,4} → aa, aaa, aaaa	Matches between n and m occurrences
`*?`	Lazy zero or more	a.*?b → ab	Non-greedy matching
`+?`	Lazy one or more	a.+?b → ab	Non-greedy matching

Anchors

Pattern	Name	Example	Description
`^`	Start of string	^hello → hello world	Matches at start of string/line
`$`	End of string	world$ → hello world	Matches at end of string/line
`\b`	Word boundary	\bword\b → the word	Matches word boundary
`\B`	Non-word boundary	\Bword → sword	Matches non-word boundary
`(?=...)`	Positive lookahead	a(?=b) → ab	Matches if followed by pattern
`(?!...)`	Negative lookahead	a(?!b) → ac	Matches if not followed by pattern
`(?<=...)`	Positive lookbehind	(?<=a)b → ab	Matches if preceded by pattern
`(?<!...)`	Negative lookbehind	(?<!a)b → cb	Matches if not preceded by pattern

Groups

Pattern	Name	Example	Description
`(...)`	Capturing group	(ab)+ → abab	Captures matched text
`(?:...)`	Non-capturing group	(?:ab)+ → abab	Groups without capturing
`(?<name>...)`	Named group	(?<year>\d{4})	Captures with name
`\1`	Backreference	(\w)\1 → aa, bb	Matches captured group again
`a\|b`	Alternation	cat\|dog → cat, dog	Matches either expression

Assertions

Pattern	Name	Example	Description
`(?=...)`	Positive lookahead	\d(?=px) → 10px	Assert pattern follows
`(?!...)`	Negative lookahead	\d(?!px) → 10em	Assert pattern does not follow
`(?<=...)`	Positive lookbehind	(?<=\$)\d+ → $100	Assert pattern precedes
`(?<!...)`	Negative lookbehind	(?<!\$)\d+ → €100	Assert pattern does not precede

Flags

Pattern	Name	Example	Description
`g`	Global	/a/g → a, a, a	Find all matches, not just first
`i`	Case insensitive	/abc/i → ABC, abc	Ignore case in matching
`m`	Multiline	/^a/m → ... a	^ and $ match line boundaries
`s`	DotAll / Singleline	/a.*b/s → a b	. matches newlines too
`u`	Unicode	/\u{1F600}/u	Enable Unicode support

What is 正则表达式速查表?

正则表达式速查表与参考是一款全面的快速参考指南，涵盖JavaScript（PCRE兼容）模式的正则表达式语法：锚点、量词、字符类、分组、反向引用和环视断言。正则表达式是文本处理的强大工具，但其密集的语法出了名地难以记忆— 即使经验丰富的开发者也经常需要查找贪婪与惰性量词之间的区别、正向前瞻的确切语法，或者哪些字符类在括号内需要转义。本速查表将语法组织为逻辑分组的部分：字符（字面量、字符类、简写）、锚点（边界）、量词（贪婪、惰性、占有）、分组（反向引用）、前瞻/后顾断言、标志（修饰符）、替换模式和常用配方。每个条目包括模式语法、通俗易懂的解释和可测试的工作示例。常用配方部分为40多个最常见的正则任务提供生产就绪的模式：邮箱验证、IPv4/IPv6地址、电话号码、URL、日期、信用卡号、密码复杂度、HTML标签提取等。模式条目包括复制按钮和到正则测试器的直接链接以进行即时实验。

When to Use 正则表达式速查表

用于构建表单验证的正则模式、查找环视语法、为常见任务查找预构建的正则配方、记忆量词行为，或向队友教授正则概念。

How to Use 正则表达式速查表

浏览分类的语法部分或搜索特定概念。每个条目显示语法、解释和工作示例。单击测试直接跳转到预加载模式的正则测试器。