Regular Expressions 101

Save & Share

Flavor

  • PCRE2 (PHP >=7.3)
  • PCRE (PHP <7.3)
  • ECMAScript (JavaScript)
  • Python
  • Golang
  • Java 8
  • .NET 7.0 (C#)
  • Rust
  • Regex Flavor Guide

Function

  • Match
  • Substitution
  • List
  • Unit Tests (2)

Tools

Sponsors
There are currently no sponsors. Become a sponsor today!
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

/
/
gmi

Test String

Code Generator

Language

Generated Code

const regex = /\b(?:(?:https?|ftp):\/\/)?(?:\S+(?::\S*)?@)?(?:(?!(?:10|127)(?:\.\d{1,3}){3})(?!(?:169\.254|192\.168)(?:\.\d{1,3}){2})(?!172\.(?:1[6-9]|2\d|3[0-1])(?:\.\d{1,3}){2})(?:[1-9]\d?|1\d\d|2[01]\d|22[0-3])(?:\.(?:1?\d{1,2}|2[0-4]\d|25[0-5])){2}(?:\.(?:[1-9]\d?|1\d\d|2[0-4]\d|25[0-4]))|(?:(?:[a-z\u00a1-\uffff0-9]-*)*[a-z\u00a1-\uffff0-9]+)(?:\.(?:[a-z\u00a1-\uffff0-9]-*)*[a-z\u00a1-\uffff0-9]+)*(?:\.(?:com|org|net|int|edu|gov|mil|arpa|biz|info|mobi|app|name|aero|jobs|museum|travel|a[c-gil-oq-uwxz]|b[abd-jmnoq-tvwyz]|c[acdf-ik-orsu-z]|d[dejkmoz]|e[ceghr-u]|f[ijkmor]|g[abd-ilmnp-uwy]|h[kmnrtu]|i[delmnoq-t]|j[emop]|k[eghimnprwyz]|l[abcikr-vy]|m[acdeghk-z]|n[acefgilopruz]|om|p[ae-hk-nrstwy]|qa|r[eosuw]|s[a-eg-or-vxyz]|t[cdfghj-prtvwz]|u[agksyz]|v[aceginu]|w[fs]|y[etu]|z[amrw]|الجزائر|հայ|বাংলা|бел|бг|中国|中國|مصر|გე|ελ|香港|भारत|بھارت|భారత్|ભારત|ਭਾਰਤ|இந்தியா|ভারত|ایران|عراق|الاردن|қаз|澳门|澳門|мкд|مليسيا|мон|المغرب|عمان|پاکستان|فلسطين|قطر|рф|السعودية|срб|新加坡|சிங்கப்பூர்|한국|ලංකා|இலங்கை|سودان|سورية|台湾|台灣|ไทย|تونس|укр|امارات|اليمن)))(?::\d{2,5})?(?:\/\S*)?\b/gmi; // Alternative syntax using RegExp constructor // const regex = new RegExp('\\b(?:(?:https?|ftp):\\\/\\\/)?(?:\\S+(?::\\S*)?@)?(?:(?!(?:10|127)(?:\\.\\d{1,3}){3})(?!(?:169\\.254|192\\.168)(?:\\.\\d{1,3}){2})(?!172\\.(?:1[6-9]|2\\d|3[0-1])(?:\\.\\d{1,3}){2})(?:[1-9]\\d?|1\\d\\d|2[01]\\d|22[0-3])(?:\\.(?:1?\\d{1,2}|2[0-4]\\d|25[0-5])){2}(?:\\.(?:[1-9]\\d?|1\\d\\d|2[0-4]\\d|25[0-4]))|(?:(?:[a-z\\u00a1-\\uffff0-9]-*)*[a-z\\u00a1-\\uffff0-9]+)(?:\\.(?:[a-z\\u00a1-\\uffff0-9]-*)*[a-z\\u00a1-\\uffff0-9]+)*(?:\\.(?:com|org|net|int|edu|gov|mil|arpa|biz|info|mobi|app|name|aero|jobs|museum|travel|a[c-gil-oq-uwxz]|b[abd-jmnoq-tvwyz]|c[acdf-ik-orsu-z]|d[dejkmoz]|e[ceghr-u]|f[ijkmor]|g[abd-ilmnp-uwy]|h[kmnrtu]|i[delmnoq-t]|j[emop]|k[eghimnprwyz]|l[abcikr-vy]|m[acdeghk-z]|n[acefgilopruz]|om|p[ae-hk-nrstwy]|qa|r[eosuw]|s[a-eg-or-vxyz]|t[cdfghj-prtvwz]|u[agksyz]|v[aceginu]|w[fs]|y[etu]|z[amrw]|الجزائر|հայ|বাংলা|бел|бг|中国|中國|مصر|გე|ελ|香港|भारत|بھارت|భారత్|ભારત|ਭਾਰਤ|இந்தியா|ভারত|ایران|عراق|الاردن|қаз|澳门|澳門|мкд|مليسيا|мон|المغرب|عمان|پاکستان|فلسطين|قطر|рф|السعودية|срб|新加坡|சிங்கப்பூர்|한국|ලංකා|இலங்கை|سودان|سورية|台湾|台灣|ไทย|تونس|укр|امارات|اليمن)))(?::\\d{2,5})?(?:\\\/\\S*)?\\b', 'gmi') const str = `http://www.answers.com/article/1194427/8-habits-of-extraordinarily-likeable-people http://www.apple.com http://www.cnn.com.au http://downloads.news.com.au http://ftp.android.co.nz http://web.dev.laterooms.com.au:1234/ http://global.news.ca http://www.apple.com http://www.apple.com:12342 localhost:1234 127.0.0.1:123 `; // 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