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

Generated Code

const regex = /^\[Error: +(?<source_path>(?<file>[^\s\n](?:[^\n:\\]+|\\.)+?)(?::(?<line>\d+)(?::(?<column>\d+)))?) *$/gm; // Alternative syntax using RegExp constructor // const regex = new RegExp('^\\[Error: +(?<source_path>(?<file>[^\\s\\n](?:[^\\n:\\\\]+|\\\\.)+?)(?::(?<line>\\d+)(?::(?<column>\\d+)))?) *$', 'gm') const str = `/usr/local/lib/node_modules/stylus/bin/stylus:685 throw err; ^ [Error: /Users/user/path/to/stylus/file/invalid.styl:34:5 30| ==/UserStyle== */ 31| 32| @-moz-document regexp("https?://(www\\\\.)?typescriptlang.org/(v2/)?docs.*\$"), 33| regexp("https?://(www\\\\.)?(staging-)?typescript\\\\.org/docs/.*\$") 34| error("compile error") -----------^ 35| compile error ] { fromStylus: true, lineno: 34, column: 5, filename: '/Users/disk0/git.local/stylus-stylus/static/test/testFiles/invalid.styl', stylusStack: '', input: '/* ==UserStyle==\\n' + '@name TypeScript Docs\\n' + '@description Expands width of code blocks and moves navigation bar fully to the left\\n' + '@version 0.0.12\\n' + '@namespace github.com/disk0/stylus/typescript.org/docs\\n' + '\\n' + '@author disk0 (github.com/disco0)\\n' + '@license MIT\\n' + '\\n' + '@preprocessor stylus\\n' + '\\n' + '@var select CodeFont "Font for code displayed on page." [\\n' + ' "Iosevka Extended*",\\n' + ' "Iosevka Expanded",\\n' + ' "Iosevka Term",\\n' + ' "Iosevka",\\n' + '\\n' + ' "SemanticHaskell",\\n' + ' "SemanticJavascript",\\n' + ' "SemanticCode",\\n' + ' "Hasklig",\\n' + '\\n' + ' "PragmataPro Mono Liga",\\n' + '\\n' + ' "monospace"\\n' + ']\\n' + '@var number CodeFontSize "Size of code in documentation" [ 14, 1, 500, 1, "px" ]\\n' + '@var number CodeFontWeight "Code font weight" [ 400, 100, 900, 100 ]\\n' + '@var number DocTextWidth "Width of text content in documentation" [ 1000, 300, 5000, 100, "px" ]\\n' + '==/UserStyle== */\\n' + '\\n' + '@-moz-document regexp("https?://(www\\\\\\\\.)?typescriptlang.org/(v2/)?docs.*\$"),\\n' + '\\t regexp("https?://(www\\\\\\\\.)?(staging-)?typescript\\\\\\\\.org/docs/.*\$")\\n' + ' error("compile error")\\n' } `; // 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