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

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 = /(^(HL\/)+HL$)|(^HLx\d+$)|(^HL$)/gmi; // Alternative syntax using RegExp constructor // const regex = new RegExp('(^(HL\\\/)+HL$)|(^HLx\\d+$)|(^HL$)', 'gmi') const str = `Guard HL/H - HL/HL L/L L/L HL/HL L/HL HL/HL L/HL HL/HL/HL L/HL/HL HL/HL HL/HL/HL HL/HL/HL/HL HL/HL HL/HL HL/HL HL/HL HL/HL/HL HL/HL/HL HL/HL/HL HL/HL HL/HL HL/HL HL/HL HL/HL/L/HL HL/HL HL/HL HL/H HL/HL HL/HL HL/HL HL/HL HL HL/HL HL/HL HL/HL HL LH/LH L/H HL/HL HL/HL HL LH/LH L/H HL/HL HL/HL HL/HL HL/HL HL/HL/HL HL/HL/HL HL HL HL HL HL (B+F)+LP+LK (B/F)+LP+LK LP+LK HL HL HL HL L HL L HL HL HL L L L L L L HL LP+LK - - - F/B+LP+LK F+LP+LK HL HL HL HL HL H HL LP+LK B+LP+LK on backturned opponent HL LP+LK HL HL HL HL HL H B/F+LP+LK LP+LK LP+LK LP+LK LP+LK LP+LK LP+LK =+ =+ LP+LK H H HL HL HL LP+LK HL HL HL LP+LK HL HL L HL L L HL LP+LK HLx2 HL HL HL B+LP+LK B/F+LP+LK B/F+LP+LK B/F+LP+LK HL HL HL HL HL LP+LK Close to Oponnent On Air LP+LK LP+LK (F)+LP+LK HL/HL/HL HL HL/HL HL LP+LK HL HL HL L L L LP+LK HL HL HL B+LP+LK HL HL (Air) LP+LK LP+LK LP+LK B+LP+LK LP+LK HL HL HL LP+LK (B/F)+LP+LK H F+LP+LK HL H/H HL HL HL HL HL/HL HL/HL/HL HL/HL/HL HL HL HL HLx7 HL/HL/HL HLx4 HLx3+HL/Lx3 Down HL/HL/HL HL HL HL HL HL HL HL HL HL HL HL HL HL HL H H HL HL HL L H H HL Impossible HL H HL HL H H H H H H H H H H H H H HL HL HL H HL HL HL L HL HL HL HL HL HL HL HL H H H H HL H HL Impossible HL HL HL H H H H H HL HL/HL HL H HL HL H H H HL H HL L H HL HL HL HL HL H HL HL H H H HL/HL HL - HL H H HL HL HL/HL HL HL HL HL HL HL HL HL HL HL Impossible Impossible Impossible HL HL HL HL HL HL HL HL HL HL HL HL L L L HL HL HL HL HL HL HL HL L L L L L L L L L L L HL L HL HL HL HL HL HL L L L L HLx1~5 HLx1~5 HLx1~5 HL HL HL HL HL HL HL HL HL HL HL HL HL HL L L L HL HL HL HL HL HL Impossible HL H H H HL HL Impossible Impossible Impossible Impossible Impossible Impossible H H HL HL HL HL HL HL HL HL HL HL L L L L HL/HL/HL HL/HL Impossible Impossible Impossible HL Impossible Impossible Impossible HL HL HL HL HL HL Hx2 HL Hx2 HL HL HL H HLx4 HL HL HLx3 HL L/HL HL/HL HL H HLx2 HL/HL HL/HL HL/HL HL/HL HL/HL HL/HL HL HLx2 HL HL HL HL H/H H HL/HL HL/HL/HL HL HL HL/HL/HL HL/H L HL/HL HL H H H(far) or L(close) H HLx2 HL HL HL - HL HL/HL/HL HL/HL/HL H HL/HL/HL/HL HL/HL/HL/HL/HL H HL/HL/HL HL HL/HL HL HL HL HL H/H H/H H/H H HL HL HL HL HL HL HL HL HL HL HL HL HL HL L L L L L L L HL HL HL HL HL L L L L L L L L L L H HL HL H H H HL HL HL HL HL HL HL HL HL HL HL HL HL HL HL HL HL HL HL HL H HL/HL/HL/HL HL/HL/HL/HL/HL HL/HL H H H H H H H H H - HL HL H H H H H H HL HL HL HL HL HL HL HL HL HL HL HL HL HL HL HL HL HL HL HL L HL/HL/HL/HL - H HLx4 H H HL HL HL HL H/H H/H H/H Lx2 Lx4 Lx2 HL HL HL/HL H/L - - HL HL HL HL HL HL HL HL HL HL HL L HL HL HL HL L L L L HL HL HL HL HL HL/HL H HL HL HL HL H HL HL HL HL HL HL HL HL HL HL HL HL HL HL HL HL HL HL HL HL HL HL HL H H H H H H H H H H H H H H H H H H H H H - - HL HL/H/H HL H HL HL HL HL HL HL HL HL HL HL HL HL HL HL HL HL H/H H HLx2 HLx1~5 HL/HL/HL HL/HL HL/HL HL/HL HL/HL HL H HL/H/H - HL Lx5 HL HL HL HL HL HL HL HL HL HL HL HL L L L L L L L L L L L HL HL HL H HL HL HL HL HL HL HL HL HL HL H H H H H H H H H H H HL HL HL HL H H H H H H H H H H H H HL HLx2 H HL HL H - HL HL HL HL HL HL HL HL HL HLx2 HLx2 HLx2 HLx3 HLx3 HLx3 - - - HL HL L HL HL HL/HL/HL HL HL HL HL HL HL/HL HL HL H H H H H H H H H H HL/H/H HL HL HL H H H H H HL HL HL HL H HL HL HL HLx2 HL/HL/HL HLx2 HL HLx2 HL/HL HL HLx2 Hx3 HL H H H - HL HL HL HL HL HL HL HL/HL/HL HL HL H H H H H H H H H HL HL HL HL HL HL H/H HL HL HLx2 L L HL H HL HL HL HL HL HL H H H H H H H H HL L H H H H HL HL HL HLx2 HL HL H Impossible HL H H H HLx2 H H HL HL HL HL H HL H H H H H H H H H H H H H H H HL H H H - H `; // 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