Regular Expressions 101

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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

/
/
gU

Test String

Code Generator

Language

Generated Code

const regex = /<article(?: class="lead")?><a href=".*" target="_top"><img(?: height=".*")? src="(.*)"(?: width=".*")? \/><\/a><h[1,2]><a href="(.*)" target="_top">(.*)<\/a><\/h[1,2]><small>By .*<\/small><small>Updated: (.*) - (.*)<\/small><div class="clear"><\/div><\/article>/g; // Alternative syntax using RegExp constructor // const regex = new RegExp('<article(?: class="lead")?><a href=".*" target="_top"><img(?: height=".*")? src="(.*)"(?: width=".*")? \\\/><\\\/a><h[1,2]><a href="(.*)" target="_top">(.*)<\\\/a><\\\/h[1,2]><small>By .*<\\\/small><small>Updated: (.*) - (.*)<\\\/small><div class="clear"><\\\/div><\\\/article>', 'g') const str = `<section class="news"><article class="lead"><a href="/2016/04/15/what-are-the-10-most-intriguing-games-of-the-2016-nfl-season/a6ikhoo/" target="_top"><img src="/_internal/cimg!0/8p7xcgnjxaoqjj4iwxfv1qlid4ag0mm" /></a><h1><a href="/2016/04/15/what-are-the-10-most-intriguing-games-of-the-2016-nfl-season/a6ikhoo/" target="_top">What are the 10 most intriguing games of the 2016 NFL season?</a></h1><small>By NATE ATKINS and ARTHUR ARKUSH</small><small>Updated: April 15, 2016 - 9:08 am</small><div class="clear"></div></article><div class="clear"></div></section><div class="bigbox ad"></div><section class="news secondary"><article><a href="/2016/04/08/green-bay-packers-cut-ilb-nate-palmer-10-game-starter-in-2015/afybdi5/" target="_top"><img height="225" src="/_internal/cimg!0/pes2uiv39y78ld1yezq38oqcz3invi8" width="400" /></a><h2><a href="/2016/04/08/green-bay-packers-cut-ilb-nate-palmer-10-game-starter-in-2015/afybdi5/" target="_top">Green Bay Packers cut ILB Nate Palmer, 10-game starter in 2015</a></h2><small>By ARTHUR ARKUSH -- aarkush@profootballweekly.com</small><small>Updated: April 8, 2016 - 4:01 pm</small><div class="clear"></div></article><article><a href="/2016/04/08/jacksonville-jaguars-aaron-colvin-and-green-bay-packers-demetri-goodson-suspended-4-games-each-for-peds/ahkwuh8/" target="_top"><img height="225" src="/_internal/cimg!0/5jn3lvqyt16zr6tg7yqrhsavrr3eh45" width="400" /></a><h2><a href="/2016/04/08/jacksonville-jaguars-aaron-colvin-and-green-bay-packers-demetri-goodson-suspended-4-games-each-for-peds/ahkwuh8/" target="_top">Jacksonville Jaguars' Aaron Colvin and Green Bay Packers' Demetri Goodson suspended 4 games each for PEDs</a></h2><small>By ARTHUR ARKUSH -- aarkush@profootballweekly.com</small><small>Updated: April 8, 2016 - 3:23 pm</small><div class="clear"></div></article></section>`; // 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