Regular Expressions 101

Save & Share

  • Regex Version: ver. 7
  • Update Regex
    ctrl+⇧+s
  • Save new Regex
    ctrl+s
  • Add to Community Library

Flavor

  • PCRE2 (PHP >=7.3)
  • PCRE (PHP <7.3)
  • ECMAScript (JavaScript)
  • Python
  • Golang
  • Java 8
  • .NET 7.0 (C#)
  • Rust
  • Regex Flavor Guide

Function

  • Match
  • Substitution
  • List
  • Unit Tests

Tools

Sponsors
There are currently no sponsors. Become a sponsor today!
An explanation of your regex will be automatically generated as you type.
Detailed match information will be displayed here automatically.
  • All Tokens
  • Common Tokens
  • General Tokens
  • Anchors
  • Meta Sequences
  • Quantifiers
  • Group Constructs
  • Character Classes
  • Flags/Modifiers
  • Substitution
  • A single character of: a, b or c
    [abc]
  • A character except: a, b or c
    [^abc]
  • A character in the range: a-z
    [a-z]
  • A character not in the range: a-z
    [^a-z]
  • A character in the range: a-z or A-Z
    [a-zA-Z]
  • Any single character
    .
  • Alternate - match either a or b
    a|b
  • Any whitespace character
    \s
  • Any non-whitespace character
    \S
  • Any digit
    \d
  • Any non-digit
    \D
  • Any word character
    \w
  • Any non-word character
    \W
  • Non-capturing group
    (?:...)
  • Capturing group
    (...)
  • Zero or one of a
    a?
  • Zero or more of a
    a*
  • One or more of a
    a+
  • Exactly 3 of a
    a{3}
  • 3 or more of a
    a{3,}
  • Between 3 and 6 of a
    a{3,6}
  • Start of string
    ^
  • End of string
    $
  • A word boundary
    \b
  • Non-word boundary
    \B

Regular Expression
No Match

/
/
gm

Test String

Code Generator

Language

Generated Code

const regex = /<a\shref="\/vn\/tags\/.*?">(?P<tags>.*?)<\/a>/gm; // Alternative syntax using RegExp constructor // const regex = new RegExp('<a\\shref="\\\/vn\\\/tags\\\/.*?">(?P<tags>.*?)<\\\/a>', 'gm') const str = `<ul class="clearfix"><li><span class="tagBoxTitle">Từ khóa: </span></li><li><a href="/vn/tags/Th%E1%BB%B1c%20ph%E1%BA%A9m/index.html">Thực phẩm</a>,&nbsp;</li><li><a href="/vn/tags/gi%C3%A1-c%E1%BA%A3/index.html">giá-cả</a>,&nbsp;</li><li><a href="/vn/tags/h%C3%A0ng-ti%C3%AAu-d%C3%B9ng/index.html">hàng-tiêu-dùng</a>,&nbsp;</li><li><a href="/vn/tags/gi%E1%BA%A3m-gi%C3%A1/index.html">giảm-giá</a>,&nbsp;</li><li><a href="/vn/tags/c%C6%B0%E1%BB%9Bc-v%E1%BA%ADn-t%E1%BA%A3i/index.html">cước-vận-tải</a>,&nbsp;</li><li><a href="/vn/tags/gi%C3%A1-x%C4%83ng/index.html">giá-xăng</a>,&nbsp;</li><li><a href="/vn/tags/x%C4%83ng-d%E1%BA%A7u/index.html">xăng-dầu</a>,&nbsp;</li><li><a href="/vn/tags/h%C3%A0ng-h%C3%B3a/index.html">hàng-hóa</a>,&nbsp;</li><li><a href="/vn/tags/CPI/index.html">CPI</a>,&nbsp;</li><li><a href="/vn/tags/T%E1%BA%BFt-nguy%C3%AAn-%C4%91%C3%A1n/index.html">Tết-nguyên-đán</a></li></ul>`; // Reset `lastIndex` if this regex is defined globally // regex.lastIndex = 0; let m; while ((m = regex.exec(str)) !== null) { // This is necessary to avoid infinite loops with zero-width matches if (m.index === regex.lastIndex) { regex.lastIndex++; } // The result can be accessed through the `m`-variable. m.forEach((match, groupIndex) => { console.log(`Found match, group ${groupIndex}: ${match}`); }); }

Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for JavaScript, please visit: https://developer.mozilla.org/en/docs/Web/JavaScript/Guide/Regular_Expressions