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 single character of: a, b, c or d
    [[ab][cd]]
  • 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]
  • Character class intersection
    [\w&&[^\d]]
  • 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
  • Match everything enclosed
    (?:...)
  • Capture everything enclosed
    (...)
  • 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 = new RegExp('\\b((0?[1-9]|[12][0-9]|3[01])[-/.\\s](0?[1-9]|1[0-2])[-/.\\s](19[0-9]{2}|200[0-9]))|((0?[1-9]|1[0-2])[-/.\\s](0?[1-9]|[12][0-9]|3[01])[-/.\\s](19[0-9]{2}|200[0-9]))|(([012][1-9]|3[01])(st|nd|rd|th)?\\s(?i:Jan|Feb|Fév|Mar|Apr|Avr|May|Mai|Jun|Juin|Jul|Juil|Aug|Sep|Sept|Oct|Nov|Dec|Déc)\\s(?:19[0-9]{2}|200[0-9]))|((?i:Jan|Feb|Fév|Mar|Apr|Avr|May|Mai|Jun|Juin|Jul|Juil|Aug|Sep|Sept|Oct|Nov|Dec|Déc)\\s(?:0?[1-9]|[12][0-9]|3[01])(st|nd|rd|th)?\\s(?:19[0-9]{2}|200[0-9]))|((0?[1-9]|[12][0-9]|3[01])(st|nd|rd|th)?\\s(?i:January|janvier|February|fevrier|février|March|mars|April|avril|May|mai|June|juin|July|juillet|August|aout|août|September|septembre|October|octobre|November|novembre|December|décembre|decembre)\\s(?:19[0-9]{2}|200[0-9]))|((?iu:January|janvier|February|fevrier|février|March|mars|April|avril|May|mai|June|juin|July|juillet|August|aout|août|September|septembre|October|octobre|November|novembre|December|décembre|decembre)\\s(?:0?[1-9]|[12][0-9]|3[01])(st|nd|rd|th)?\\s(?:19[0-9]{2}|200[0-9]))|(0?[1-9]|1[0-2])[-\\/.\\s](0?[1-9]|[12][0-9]|3[01])[-\\/.\\s](19|20)0[0-9]|(19|20)0[0-9][-\\/.\\s](0?[1-9]|1[0-2])[-\\/.\\s](0?[1-9]|[12][0-9]|3[01])\\b ', 'gm') const str = `April 2nd 2008 April 2 2008 April 02 2008 2009-01-01 31-03-2009 03-31-2009 31 March 2009 March 31 2009 31 mars 2009 May 10th 1989 April 2nd 2008 2009.01.01 2009 1 31 31st december 2009 31 décembre 2009 31 Decembre 2009 2009/02/01 2009.01.01 2009 01 01 31 03 2009 12 31 2009`; // 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