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

/
/
gm

Test String

Code Generator

Language

Generated Code

const regex = /^.*?((?:\s+\d+\.\s+Nx?[a-h][1-8]\s+[RBKQN]?x?[a-h][1-8]){2,}).*$/gm; // Alternative syntax using RegExp constructor // const regex = new RegExp('^.*?((?:\\s+\\d+\\.\\s+Nx?[a-h][1-8]\\s+[RBKQN]?x?[a-h][1-8]){2,}).*$', 'gm') const str = `[Event "Live Chess"] [Site "Chess.com"] [Date "2023.02.17"] [Round "-"] [White "-"] [Black "-"] [Result "1-0"] [WhiteElo "925"] [BlackElo "939"] [TimeControl "180+2"] [EndTime "17:39:13 PST"] [Termination "- won by checkmate"] e4 e5 2. Nc3 d6 3. Bc4 h6 4. d3 Nc6 5. f4 Qe7 6. Nf3 Be6 7. f5 Bxc4 8. dxc4 O-O-O 9. b3 Nf6 10. O-O g5 11. fxg6 fxg6 12. Nh4 g5 13. Ng6 Qg7 14. Nxh8 Qxh8 15. Nd5 Nxd5 16. exd5 Nd4 17. c3 Nxb3 18. axb3 a6 19. b4 Be7 20. Qg4+ Kb8 21. b5 axb5 22. cxb5 b6 23. Qa4 Kc8 24. Qa8+ Kd7 25. Qc6+ Kc8 26. Ra8# 1-0 [Event "Live Chess"] [Site "Chess.com"] [Date "2023.02.17"] [Round "-"] [White "-"] [Black "-"] [Result "1-0"] [WhiteElo "914"] [BlackElo "841"] [TimeControl "180+2"] [EndTime "19:06:57 PST"] [Termination "- won by resignation"] e4 e5 2. Nc3 Nc6 3. Bc4 Nf6 4. d3 Bc5 5. Na4 Bb4+ 6. c3 Be7 7. f4 b5 8. Bxb5 a6 9. Bc4 O-O 10. f5 d5 11. exd5 Nxd5 12. Nf3 Bxf5 13. O-O Bc5+ 14. Nxc5 Nf4 15. Nxe5 Nxe5 16. Rxf4 Bg4 17. Rxg4 Nxg4 18. Qxg4 Re8 19. Bh6 g6 1-0`; // 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