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

r'''
'''
gmxi

Test String

Code Generator

Language

Generated Code

const regex = new RegExp('(?#First, match the protocol) (?:https?|ftp):// (?#Next, check for optional username and/or password) (?#Note: The following two char classes are functionally equivalent) (?:[\\x21-\\x39\\x3b-\\x3f\\x41-\\x7e]+(?::[!-9;-?A-~]+)?@)? (?#Next, let\\'s match the domain [with support for Punycode ]) (?:xn--[0-9a-z]+|[0-9A-Za-z_-]+\\.)*(?:xn--[0-9a-z]+|[0-9A-Za-z-]+)\\.(?:xn--[0-9a-z]+|[0-9A-Za-z]{2,10}) (?#Let\\'s match on optional port) (?::(?:6553[0-5]|655[0-2]\\d|65[0-4]\\d{2}|6[0-4]\\d{3}|[1-5]\\d{4}|[1-9]\\d{1,3}|\\d))? (?#Next, let\\'s match on the path) (?:/[\\x21\\x22\\x24\\x25\\x27-x2e\\x30-\\x3b\\x3e\\x40-\\x5b\\x5d-\\x7e]*)* (?#Next, let\\'s match on an anchor) (?:\\#[\\x21\\x22\\x24\\x25\\x27-x2e\\x30-\\x3b\\x3e\\x40-\\x5b\\x5d-\\x7e]*)? (?#Last, but not least, we match on URI params) (?:\\?[\\x21\\x22\\x24\\x25\\x27-\\x2e\\x30-\\x3b\\x40-\\x5b\\x5d-\\x7e]+=[\\x21\\x22\\x24\\x25\\x27-\\x2e\\x30-\\x3b\\x40-\\x5b\\x5d-\\x7e]*)? (?#Additional params) (?:&[\\x21\\x22\\x24\\x25\\x27-\\x2e\\x30-\\x3b\\x40-\\x5b\\x5d-\\x7e]+=[\\x21\\x22\\x24\\x25\\x27-\\x2e\\x30-\\x3b\\x40-\\x5b\\x5d-\\x7e]*)* ', 'gmi') const str = `https://thechildrenareourfuture.org/#SomeRandomAnchorGoesHere http://user:pass@example.com:8080/omega:33 https://www.google.com:65535/ https://www.google.com:42069/ https://www.google.com:9876/ https://www.google.com:59999/ https://www.google.com:10000/ https://www.google.com:1234/ https://www.google.com:53/ https://www.google.com:123/ https://www.google.com:0/ ftp://username:password@example.com:21/path/here/to/file.tar.gz http://google.com?redirect=https%3A%2F%2Flocalhost%3A8080&var2=somethingelse https://john.smith@github.com/UserGroup/repo.git https://mattermost.com:8065/team/messages/@john.smith https://punycode.xn--j6w193g smtp://somesite.com/myFile.php SMTP://SOMESITE.COM/MYFILE.PHP unknown://somesite.com/fiLeNuM12345.php //SomeSite.ru/foO.php ://SomeOtherSite.oRg/baRR.php https://_sub1.sub2.sub3.s-u_b4.domain.com http://username:password@subdomain.domain.co.uk/path/to/file.html#Anchor1?key1=value1&key2=value2`; // 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