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

/
/
mg

Test String

Code Generator

Language

Generated Code

const regex = /^\/([a-zA-Z]{2}-[a-zA-Z]{2})\/cms\/api\/preview([a-zA-Z0-9-_=\/]*)(\?)?(.*)/mg; // Alternative syntax using RegExp constructor // const regex = new RegExp('^\\\/([a-zA-Z]{2}-[a-zA-Z]{2})\\\/cms\\\/api\\\/preview([a-zA-Z0-9-_=\\\/]*)(\\?)?(.*)', 'mg') const str = `/en-US/cms/api/preview/pippo/paperino/pluto/minni/amelia#user=Artibani?qui=qua&quo=qui /en-US/cms/api/preview/pippo/paperino/pluto/minni/amelia#/user=Artibani?qui=qua&quo=qui /en-US/cms/api/preview/pippo/paperino/pluto/DePaperoni=ricco/amelia/#user/Artibani?qui=qua&quo=qui /en-US/cms/api/preview/pippo/paperino/pluto/DePaperoni=ricco/amelia/#/user=Artibani?qui=qua&quo=qui /en-US/cms/api/preview/pippo/pluto23?qua=qui /en-US/cms/api/preview/pippo-clarabella/EN-us/123??? /en-US/cms/api/preview/pippo/pluto-orazio? /en-US/cms/api/preview/pippo/pico-archimede/ /en-US/cms/api/preview/pippo/pico/archimede /en-US/cms/api/preview/pippo/paperino/pluto/minni/amelia#user/Faraci /en-US/cms/api/preview/pippo/paperino/pluto/minni/amelia/#user=Faraci /en-US/cms/api/preview /en-US/cms/api/preview/ /en-US/cms/api/preview? /en-US/cms/api/preview/? /en-US/cms/api/preview#user=Artibani?qui=qua&quo=qui&cap_paperopoli=123 /en-US/cms/api/preview/#user/Artibani?qui=qua&quo=qui&cap_paperopoli=123 /en-US/cms/api/preview#/user=Artibani?qui=qua&quo=qui&cap_paperopoli=123 /en-US/cms/api/preview/#/user=Artibani?qui=qua&quo=qui&cap_paperopoli=123 /en-US/cms/api/preview#user=Faraci /en-US/cms/api/preview#/user=Faraci /en-US/cms/api/preview/#/user=Faraci /en-US/cms/api/preview/pippo/paperino/pluto/minni/amelia?qui=qua&quo=qui /en-US/cms/api/preview/pippo/paperino/pluto/DePaperoni=ricco/paperoga?qui=qua&quo=qui /en-US/cms/api/preview/pippo/pluto23?qua=qui /en-US/cms/api/preview/pippo-clarabella/EN-us/123??? /en-US/cms/api/preview/pippo/pluto-orazio? /en-US/cms/api/preview/pippo/pico-archimede/? /en-US/cms/api/preview/pippo/pico-archimede/ /en-US/cms/api/preview/pippo/pico/archimede /en-US/cms/api/preview/pippo/paperino/pluto/minni/amelia#user=Faraci /en-US/cms/api/preview/pippo/paperino/pluto/minni/amelia/#user/Faraci /en-US/cms/api/preview/pippo/paperino/pluto/minni/amelia/#/user=Faraci /en-US/cms/api/preview /en-US/cms/api/preview/ /en-US/cms/api/preview? /en-US/cms/api/preview/? /en-US/cms/api/preview#user=Faraci /en-US/cms/api/preview/#user/&Faraci NOT OK /en-US/cms/api/preview?#user=Faraci /en-US/cms/api/preview?#/user=Faraci /en-US/cms/api/preview?/#/user=Faraci /en-US/cms/api/preview/?#user=Faraci /en-US/cms/api/preview/?#/user/Faraci /en-US/cms/api/preview/?/#/user=Faraci /en-US/cms/api/preview/pippo/paperino/pluto/minni/amelia?qui=qua&quo=qui#userArtibani /en-US/cms/api/preview/pippo/paperino/pluto/minni/amelia/?qui=qua&quo=qui#user/Artibani /en-US/cms/api/preview?qui=qua&quo=qui#user/Artibani /en-US/cms/api/preview/?qui=qua&quo=qui#user=Artibani /en-US/cms/api/preview?#user=Faraci /en-US/cms/api/preview/?#user/Faraci Output for Nginx: /preview/\$2?culture=\$1&\$4`; // 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