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 = /^(?:(52\-)|(1\-))?(\()?(?(1)[0-9]{2,3}|[2-9][0-9]{2})(?(3)\)\s?|(\-|[.]|\s|))(?(1)[0-9]|[2-9])[0-9]{2}(?(4)\4|(?:\-|[.]|\s)?)[0-9]{4}(\s?(?:x|ext|ext.|extension|Ext|Ext.|Extension|#)\s?[0-9]+)?$/gm; // Alternative syntax using RegExp constructor // const regex = new RegExp('^(?:(52\\-)|(1\\-))?(\\()?(?(1)[0-9]{2,3}|[2-9][0-9]{2})(?(3)\\)\\s?|(\\-|[.]|\\s|))(?(1)[0-9]|[2-9])[0-9]{2}(?(4)\\4|(?:\\-|[.]|\\s)?)[0-9]{4}(\\s?(?:x|ext|ext.|extension|Ext|Ext.|Extension|#)\\s?[0-9]+)?$', 'gm') const str = `Regular valid formats 225-586-7777 (223)249-4444 (223) 234-3344 223.456.2222 2253451111 223 334 4444 1-325-586-7777 1-(923)249-4444 1-(923) 234-3344 1-923.456.2222 1-9253451111 1-923 234 4444 52-125-586-7777 52-(123)249-4444 52-(123) 234-3344 52-123.456.2222 52-1253451111 52-123 134 4444 Valid formats with extensions 1-800-661-3696 x14700 1-800-661-3696x14700 1-800-661-3696 Extension 14700 1-800-661-3696 ext14700 325-586-7777 x123 (323)249-4444x123 (323) 234-3344 Ext 123 323.456.2222 ext 124 3253451111ext. 123 323 334 4444extension234 (223)456 7891 x 123 (223)456 7891 ext 123 (223)456 7891 ext. 123 (223)456 7891 Ext 123 (223)456 7891 Ext. 123 (910)456-8970 x12 (910)456-8970 #12 (910)456-8970 extension12456 (910)456-8970 Extension 12456 Invalid formats 444000-1111 444-0001111 444.000-1111 444000 1111 444 0001111 444 000.1111 444.0001111 444000.1111 444-000.1111 (4440001111 444)0001111 440001111 444000111111 125-586-7777 (123)249-4444 (123) 234-3344 123.456.2222 1253451111 123 134 4444 125-586-7777 (123)249-4444 (123) 234-3344 123.456.2222 1253451111 123 134 4444 Invalid formats with extensions 12-125-586-7777 12-(123)249-4444 12-(123) 234-3344 12-123.456.2222 12-1253451111 12-123 134 4444 12-444000-1111 12-444-0001111 12-444.000-1111 12-444000 1111 12-444 0001111 12-444 000.1111 12-444.0001111 12-444000.1111 12-444-000.1111 12-(4440001111 12-444)0001111 12-440001111 12-444000111111 1-888-720-1275 x2 x2 1-888-720-1275 2 1-888-720-1275 x 1-888-720-1275 Ext 888-720-1275x 1-444000-1111 1-444-0001111 1-444.000-1111 1-444000 1111 1-444 0001111 1-444 000.1111 1-444.0001111 1-444000.1111 1-444-000.1111 1-(4440001111 1-444)0001111 1-440001111 1-444000111111`; // 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