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

/
/
mg

Test String

Code Generator

Language

Generated Code

const regex = /^https?:\/\/(((?!desktop).*\.)?(githubusercontent|githubstatus|github)\.(?!io|myshopify|blog|community)).*/mg; // Alternative syntax using RegExp constructor // const regex = new RegExp('^https?:\\\/\\\/(((?!desktop).*\\.)?(githubusercontent|githubstatus|github)\\.(?!io|myshopify|blog|community)).*', 'mg') const str = `https://github.com/DarkThemeHub/GithubDarkTheme/ https://github.com/DarkThemeHub/ https://github.com/ https://pages.github.com/ https://raw.githubusercontent.com/DarkThemeHub/GithubDarkTheme/master/LICENCE http://pages.github.com/ https://www.githubstatus.com/ https://developer.github.com/ https://help.github.com/en https://support.github.com/ #should not match following https://www.google.com/search?q=github&rlz=1C1PRFI_enGB877GB877&oq=github&aqs=chrome..69i57j69i60l6j69i65.1527j0j4&sourceid=chrome&ie=UTF-8 https://www.google.com/search?rlz=1C1PRFI_enGB877GB877&sxsrf=ACYBGNTdOnxT4FtUGQrGBdsLwdwP4vqYLQ%3A1578868177870&ei=0Z0bXs_gNOGGhbIProal0A8&q=github.com&oq=github.com&gs_l=psy-ab.3..35i39j0l9.103.358..1309...0.0..0.133.404.2j2......0....1..gws-wiz.......0i7i30.JWbDVwMFzHg&ved=0ahUKEwiPjY6njv_mAhVhQ0EAHS5DCfoQ4dUDCAs&uact=5 https://www.google.com/search?sxsrf=ACYBGNQ6mBQXfPi8Zuwm1WavyLIOTTNSKw%3A1578869437012&ei=vaIbXog91MHyAomUivgJ&q=github.com&oq=github.com&gs_l=psy-ab.3..35i39j0l9.1173.2046..2166...0.2..0.59.221.4......0....1..gws-wiz.......0i71j0i273.I-jQ27pFmlA&ved=0ahUKEwjIj8L_kv_mAhXUoFwKHQmKAp8Q4dUDCAs&uact=5 https://desktop.github.com/ https://github.myshopify.com/ https://sagioto.github.io/maven2gradle/ https://jspenguin2017.github.io/uBlockProtector/ https://www.howtogeek.com/180167/htg-explains-what-is-github-and-what-do-geeks-use-it-for/ https://twitter.com/github?something https://serokell.io/blog/comparison-of-github-and-gitlab https://github.community/`; // 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