Regular Expressions 101

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Function

  • Match
  • Substitution
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  • Unit Tests (8)
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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
Processing...

Test String

Code Generator

Language

Generated Code

const regex = /magnet:\?((&?xt\.?\d*=urn:[A-Za-z0-9][A-Za-z0-9-]{0,31}:[A-Fa-f0-9]{20,50})|(&?(dn|tr|xl|ws|as|xs|kt|mt)=[A-Za-z0-9\-._%+;=:?\/]+)&?)+$/g; // Alternative syntax using RegExp constructor // const regex = new RegExp('magnet:\\?((&?xt\\.?\\d*=urn:[A-Za-z0-9][A-Za-z0-9-]{0,31}:[A-Fa-f0-9]{20,50})|(&?(dn|tr|xl|ws|as|xs|kt|mt)=[A-Za-z0-9\\-._%+;=:?\\\/]+)&?)+$', 'g') const str = `magnet:?xt=urn:btih:6B5FFA38E0C811E0738697BEC13DDDA57A60FCB4&dn=Taboo.UK.Season.1.S01.1080p.AMZN.WEBRip.5.1.HEVC.x265-GIRAYS&tr=udp%3A%2F%2Ftracker.coppersurfer.tk%3A6969%2Fannounce&tr=udp%3A%2F%2F9.rarbg.to%3A2920%2Fannounce&tr=udp%3A%2F%2Ftracker.opentrackr.org%3A1337&as=udp%3A%2F%2Ftracker.internetwarriors.net%3A1337%2Fannounce&tr=udp%3A%2F%2Ftracker.leechers-paradise.org%3A6969%2Fannounce&tr=udp%3A%2F%2Ftracker.coppersurfer.tk%3A6969%2Fannounc/e&tr=udp%3A%2F%2Ftracker.pirateparty.gr%3A6969%2Fannounce&tr=udp%3/A%2F%2Ftracker.cyberia.is%3A6969%2Fannounce&xt=urn:btih:6B5FFA38E0C811E0738697BEC13DDDA57A60FCB4&xt=urn:btih:6B5FFA38E0C811E0738697BEC13DDDA57A60FCB4&xs=dchub://example.org&as=http%3A%2F%2Fdownload.wikimedia.org%2Fmediawiki%2F1.15%2Fmediawiki-1.15.1.tar.gz&xl=10826029&dn=mediawiki-1.15.1.tar.gz`; // 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