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 single character of: a, b, c or d
    [[ab][cd]]
  • 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]
  • Character class intersection
    [\w&&[^\d]]
  • 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 = new RegExp('(?im)^(?<c1>\\"?)\\w+(?:[\\W&&[^@]]?)\\w+\\k<c1>@(?:\\[?(?:\\d{3}\\.?){0,4}\\]?|(?:[\\w&&[^\\d]]+[\\.\\-]?)*(?<=\\.\\w{2,6}))$', 'g') const str = `List of Valid Email Addresses email@example.com firstname.lastname@example.com email@subdomain.example.com firstname+lastname@example.com email@123.123.123.123 email@[123.123.123.123] "email"@example.com 1234567890@example.com email@example-one.com _______@example.com email@example.name email@example.museum email@example.co.jp firstname-lastname@example.com List of Strange Valid Email Addresses much.”more\\ unusual”@example.com very.unusual.”@”.unusual.com@example.com very.”(),:;<>[]”.VERY.”very@\\\\ "very”.unusual@strange.example.com List of Invalid Email Addresses plainaddress #@%^%#\$@#\$@#.com @example.com Joe Smith <email@example.com> email.example.com email@example@example.com .email@example.com email.@example.com email..email@example.com あいうえお@example.com email@example.com (Joe Smith) email@example email@-example.com email@example.web email@111.222.333.44444 email@example..com Abc..123@example.com List of Strange Invalid Email Addresses ”(),:;<>[\\]@example.com just”not”right@example.com this\\ is"really"not\\allowed@example.com`; // 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