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

/
/
g

Test String

Code Generator

Language

Generated Code

const regex = /\/\*[^*]*\*+([^\/*][^*]*\*+)*\/ /g; // Alternative syntax using RegExp constructor // const regex = new RegExp('\\\/\\*[^*]*\\*+([^\\\/*][^*]*\\*+)*\\\/ ', 'g') const str = `/* = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = */ /* @TODO: - Notes... */ /* = = = Set Base Font Size = = = So 1em = 10px / 1.8em = 18px etc */ body { font-size: 62.5% } body, ul, li { color: #333333; font-family: 'Open Sans', verdana, arial, helvetica, helve, sans-serif; font-weight: 400; /* font-size: 1.4em; Default font = 14px normal weight Open Sans using #333333 */ line-height: 1.25em; } body { margin: 0; /* Nav bar and footer need to fit edge to edge so no margins! */ padding: 0; top: 0; border-bottom: 1px #1C1C1C solid; /* To remove white space under the popup footer */ } /* = = = Typography = = = */ /* Font choice was carefully considered, Open Sans is very popular so many visitors will already have it cached. */ /* Monda & Shadows into light are also quite popular so may be cached too */ /* = = = Headings = = = */ h1, h2, h3, h4, h5, h6 { font-family: 'Monda', 'Trebuchet MS', verdana, arial, helvetica, helve, sans-serif; font-weight: 400; line-height: 1.2em; letter-spacing: 1px; color: #333333; margin-top: 10px; margin-bottom: 20px; } `; // 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