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

/
/
gm

Test String

Code Generator

Language

Generated Code

const regex = /^(\d{4}|\+\d{6})(?:-(\d{2})(?:-(\d{2})(?:T(\d{2}):(\d{2}):(\d{2})(?:\.{0,1})(\d{0,})(Z|([\-+])(\d{2})(?::{0,1})(\d{2}))?)?)?)?$/gm; // Alternative syntax using RegExp constructor // const regex = new RegExp('^(\\d{4}|\\+\\d{6})(?:-(\\d{2})(?:-(\\d{2})(?:T(\\d{2}):(\\d{2}):(\\d{2})(?:\\.{0,1})(\\d{0,})(Z|([\\-+])(\\d{2})(?::{0,1})(\\d{2}))?)?)?)?$', 'gm') const str = `HOLY CRAP - THIS LOOKS PERFECT FOR ISO + YYYY-MM-DD! 2015-08-10 2015-10-08 12015-08-10 -2015-08-10 +2015-08-10 0015-08-10 1582-10-10 2015-02-28 2016-02-29 2000-02-29 0000-02-29 -2000-02-29 -2016-02-29 200000-02-29 2016-366 2000-366 0000-366 -2016-366 -2000-366 2015-081 2015-W33-1 2015-W53-7 2015-08-10 2016-11-09T01:00:23Z 2083-06-12T02:49:23.473Z 2020-06-12T02:49:23.473Z 2083-06-12T02:49:23 2020-06-12T02:49:23Z 2000-01-01 2000-01-99 12/01/1986 02/29/2016 02/29/2015 13/31/1986 12/31/1980 1/32/2015 1/31/2015 01012016 01/01/2016 1/1/2016 1/1/16 01/01/16 01-01-2016 1-1-2016 1-1-16 01-01-16 `; // 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