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 = /(([a-zA-Z0-9_\-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([a-zA-Z0-9\-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)(\s*;\s*|\s*$))*/gm; // Alternative syntax using RegExp constructor // const regex = new RegExp('(([a-zA-Z0-9_\\-\\.]+)@((\\[[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.)|(([a-zA-Z0-9\\-]+\\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\\]?)(\\s*;\\s*|\\s*$))*', 'gm') const str = `a@a.c a@a.co sbreedebd@home.pl sgerrensbe@free.fr eishakbf@skyrock.com dstansallbg@japanpost.jp mbrittanbh@amazon.co.uk slauridsenbi@home.pl dgrabbambj@imageshack.us etossellbk@apple.com smoodycliffebl@sogou.com rtoothillbm@wisc.edu asebbornbn@infoseek.co.jp dgherardescibo@jalbum.net aarnaldybp@europa.eu aballantinebq@bigcartel.com cgiraudatbr@phpbb.com hmaccoughenbs@answers.com emattessenbt@dot.gov saronowbu@exblog.jp ckorneichukbv@berkeley.edu nroderigobw@yale.edu ealeksandrevbx@netvibes.com ebolterby@eepurl.com cgaitherbz@theatlantic.com sfeedomec0@shutterfly.com ahatfullc1@ocn.ne.jp mbythwayc2@whitehouse.gov mleitherc3@dyndns.org gtouretc4@icq.com lmcnaec5@cam.ac.uk tculveyc6@si.edu fportwainc7@themeforest.net eshivellc8@xing.com mrheltonc9@howstuffworks.com rrenodenca@walmart.com ibaudcb@apple.com amckerncc@domainmarket.com aszymczykcd@vk.com edittyce@patch.com eibertcf@cyberchimps.com apagencg@google.cn bcousinsch@elpais.com edockrellci@kickstarter.com peasterlingcj@vkontakte.ru mmoenck@mail.ru nstitwellcl@admin.ch mreginacm@techcrunch.com fbindoncn@nps.gov vpocklingtonco@seattletimes.com lbarabichcp@privacy.gov.au fmcbeathcq@thetimes.co.uk jbohillscr@bandcamp.com aworkescs@amazon.de mmarusyakct@zdnet.com lmcaleescu@simplemachines.org bdemetzcv@illinois.edu jdominiquecw@economist.com easlottcx@ftc.gov adewhirstcy@marriott.com mstaddomcz@slideshare.net aealamd0@ibm.com dweblind1@youtube.com palasdaird2@unesco.org rfrearsond3@disqus.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