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

Substitution

Processing...

Code Generator

Language

Generated Code

const regex = /^\s*(?:(?:\S\s?)*\s+){2}(?:L\d+:\s*)?| +(?= )/gm; // Alternative syntax using RegExp constructor // const regex = new RegExp('^\\s*(?:(?:\\S\\s?)*\\s+){2}(?:L\\d+:\\s*)?| +(?= )', 'gm') const str = `1FC8 0801 000A BTst.B #\$A, D1 1FCC 6608 BNE.B L315 1FCE 0240 00FF And #\$FF, D0 1FD2 43F8 0400 Lea.L (DispatchTab), A1 1FD6 E548 L315: LsL #\$2, D0 1FD8 2388 0000 Move.L A0, \$0(A1,D0.W) 1FDC 7000 MoveQ.L #\$0, D0 1FDE 4E75 Rts 1FE0 6102 L316: Bsr.B P42 1FE2 60F2 Bra.B L315 P42: 1FE4 0240 01FF And #\$1FF, D0 1FE8 43F8 0C00 Lea.L (ToolDispTable), A1 1FEC 0C40 0057 Cmp #\$57, D0 1FF0 6212 BHI.B L318 1FF2 670C BEQ.B L317 1FF4 0C40 004F Cmp #\$4F, D0 1FF8 6306 BLS.B L317 1FFA 0C40 0054 Cmp #\$54, D0 1FFE 6604 BNE.B L318 2000 43F8 0400 L317: Lea.L (DispatchTab), A1 2004 4E75 L318: Rts 2006 61DC L319: Bsr.B P42 2008 601C Bra.B L320 P_tGetTrapAddress: 200A 0801 0009 BTst.B #\$9, D1 200E 67F6 BEQ.B L319 2010 0240 01FF And #\$1FF, D0 2014 43F8 0C00 Lea.L (ToolDispTable), A1 2018 0801 000A BTst.B #\$A, D1 201C 6608 BNE.B L320 201E 0240 00FF And #\$FF, D0 2022 43F8 0400 Lea.L (DispatchTab), A1 2026 E548 L320: LsL #\$2, D0 2028 2071 0000 Move.L \$0(A1,D0.W), A0 202C 7000 MoveQ.L #\$0, D0 202E 4E75 Rts`; const subst = ``; // The substituted value will be contained in the result variable const result = str.replace(regex, subst); console.log('Substitution result: ', result);

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