Regular Expressions 101

Save & Share

  • Regex Version: ver. 1
  • Update Regex
    ctrl+⇧+s
  • Save new Regex
    ctrl+s
  • Add to Community Library

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

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

/
/
gm

Test String

Code Generator

Language

Generated Code

const regex = /\x21[ -\x20]|\x22[ -\x21]|\x23[ -\x22]|\x24[ -\x23]|\x25[ -\x24]|\x26[ -\x25]|\x27[ -\x26]|\x28[ -\x27]|\x29[ -\x28]|\x2a[ -\x29]|\x2b[ -\x2a]|\x2c[ -\x2b]|\x2d[ -\x2c]|\x2e[ -\x2d]|\x2f[ -\x2e]|\x30[ -\x2f]|\x31[ -\x30]|\x32[ -\x31]|\x33[ -\x32]|\x34[ -\x33]|\x35[ -\x34]|\x36[ -\x35]|\x37[ -\x36]|\x38[ -\x37]|\x39[ -\x38]|\x3a[ -\x39]|\x3b[ -\x3a]|\x3c[ -\x3b]|\x3d[ -\x3c]|\x3e[ -\x3d]|\x3f[ -\x3e]|\x40[ -\x3f]|\x41[ -\x40]|\x42[ -\x41]|\x43[ -\x42]|\x44[ -\x43]|\x45[ -\x44]|\x46[ -\x45]|\x47[ -\x46]|\x48[ -\x47]|\x49[ -\x48]|\x4a[ -\x49]|\x4b[ -\x4a]|\x4c[ -\x4b]|\x4d[ -\x4c]|\x4e[ -\x4d]|\x4f[ -\x4e]|\x50[ -\x4f]|\x51[ -\x50]|\x52[ -\x51]|\x53[ -\x52]|\x54[ -\x53]|\x55[ -\x54]|\x56[ -\x55]|\x57[ -\x56]|\x58[ -\x57]|\x59[ -\x58]|\x5a[ -\x59]|\x5b[ -\x5a]|\x5c[ -\x5b]|\x5d[ -\x5c]|\x5e[ -\x5d]|\x5f[ -\x5e]|\x60[ -\x5f]|\x61[ -\x60]|\x62[ -\x61]|\x63[ -\x62]|\x64[ -\x63]|\x65[ -\x64]|\x66[ -\x65]|\x67[ -\x66]|\x68[ -\x67]|\x69[ -\x68]|\x6a[ -\x69]|\x6b[ -\x6a]|\x6c[ -\x6b]|\x6d[ -\x6c]|\x6e[ -\x6d]|\x6f[ -\x6e]|\x70[ -\x6f]|\x71[ -\x70]|\x72[ -\x71]|\x73[ -\x72]|\x74[ -\x73]|\x75[ -\x74]|\x76[ -\x75]|\x77[ -\x76]|\x78[ -\x77]|\x79[ -\x78]|\x7a[ -\x79]|\x7b[ -\x7a]|\x7c[ -\x7b]|\x7d[ -\x7c]|\x7e[ -\x7d]|\x7f[ -\x7e]/gm; // Alternative syntax using RegExp constructor // const regex = new RegExp('\\x21[ -\\x20]|\\x22[ -\\x21]|\\x23[ -\\x22]|\\x24[ -\\x23]|\\x25[ -\\x24]|\\x26[ -\\x25]|\\x27[ -\\x26]|\\x28[ -\\x27]|\\x29[ -\\x28]|\\x2a[ -\\x29]|\\x2b[ -\\x2a]|\\x2c[ -\\x2b]|\\x2d[ -\\x2c]|\\x2e[ -\\x2d]|\\x2f[ -\\x2e]|\\x30[ -\\x2f]|\\x31[ -\\x30]|\\x32[ -\\x31]|\\x33[ -\\x32]|\\x34[ -\\x33]|\\x35[ -\\x34]|\\x36[ -\\x35]|\\x37[ -\\x36]|\\x38[ -\\x37]|\\x39[ -\\x38]|\\x3a[ -\\x39]|\\x3b[ -\\x3a]|\\x3c[ -\\x3b]|\\x3d[ -\\x3c]|\\x3e[ -\\x3d]|\\x3f[ -\\x3e]|\\x40[ -\\x3f]|\\x41[ -\\x40]|\\x42[ -\\x41]|\\x43[ -\\x42]|\\x44[ -\\x43]|\\x45[ -\\x44]|\\x46[ -\\x45]|\\x47[ -\\x46]|\\x48[ -\\x47]|\\x49[ -\\x48]|\\x4a[ -\\x49]|\\x4b[ -\\x4a]|\\x4c[ -\\x4b]|\\x4d[ -\\x4c]|\\x4e[ -\\x4d]|\\x4f[ -\\x4e]|\\x50[ -\\x4f]|\\x51[ -\\x50]|\\x52[ -\\x51]|\\x53[ -\\x52]|\\x54[ -\\x53]|\\x55[ -\\x54]|\\x56[ -\\x55]|\\x57[ -\\x56]|\\x58[ -\\x57]|\\x59[ -\\x58]|\\x5a[ -\\x59]|\\x5b[ -\\x5a]|\\x5c[ -\\x5b]|\\x5d[ -\\x5c]|\\x5e[ -\\x5d]|\\x5f[ -\\x5e]|\\x60[ -\\x5f]|\\x61[ -\\x60]|\\x62[ -\\x61]|\\x63[ -\\x62]|\\x64[ -\\x63]|\\x65[ -\\x64]|\\x66[ -\\x65]|\\x67[ -\\x66]|\\x68[ -\\x67]|\\x69[ -\\x68]|\\x6a[ -\\x69]|\\x6b[ -\\x6a]|\\x6c[ -\\x6b]|\\x6d[ -\\x6c]|\\x6e[ -\\x6d]|\\x6f[ -\\x6e]|\\x70[ -\\x6f]|\\x71[ -\\x70]|\\x72[ -\\x71]|\\x73[ -\\x72]|\\x74[ -\\x73]|\\x75[ -\\x74]|\\x76[ -\\x75]|\\x77[ -\\x76]|\\x78[ -\\x77]|\\x79[ -\\x78]|\\x7a[ -\\x79]|\\x7b[ -\\x7a]|\\x7c[ -\\x7b]|\\x7d[ -\\x7c]|\\x7e[ -\\x7d]|\\x7f[ -\\x7e]', 'gm') const str = `ae ea za aA f\$ `; // 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