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

/
/
img

Test String

Code Generator

Language

Generated Code

const regex = /(gmai|ggmail|gmial|gmaol|gmil|iclould|gmeil|iclouds|icoud|hotmial|yahio|gmell|hotmil|gmailz|iclound|gmaio|gmile|gmaul|iclud|gmsil|gamil|ail|gnail|yhoo|gmal|gmaill|yaho|yshoo|gimail|gemail|gmail\.com)\.(com)$/img; // Alternative syntax using RegExp constructor // const regex = new RegExp('(gmai|ggmail|gmial|gmaol|gmil|iclould|gmeil|iclouds|icoud|hotmial|yahio|gmell|hotmil|gmailz|iclound|gmaio|gmile|gmaul|iclud|gmsil|gamil|ail|gnail|yhoo|gmal|gmaill|yaho|yshoo|gimail|gemail|gmail\\.com)\\.(com)$', 'img') const str = `gmai.com gmial.com gmaol.com gmil.com iclould.com gmeil.com iclouds.com icoud.com ggmail.com hotmial.com yahio.com gmell.com hotmil.com gmailz.com iclound.com gmaio.com gmile.com gmaul.com iclould.com gmaul.com iclud.com gmsil.com yahoo.con gamil.com gmail.co ail.com gnail.com gmal.com gail.com yhoo.com hmail.com gmaill.com yaho.com yshoo.com g.mail.com yahoo.co g-mail.com gmail.comm gmail.vom icloud.con hotmail.con gimail.com gmail.cim gemail.com gmail.com.com`; // 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