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

Substitution

Processing...

Code Generator

Language

Generated Code

const regex = /trans\('([a-zA-Z]+[.])+(testword|testword2|testword1|testword3)'\)/g; // Alternative syntax using RegExp constructor // const regex = new RegExp('trans\\(\'([a-zA-Z]+[.])+(testword|testword2|testword1|testword3)\'\\)', 'g') const str = `Welcome to RegExr v2.1 by gskinner.com, proudly hosted by Media Temple! Edit the Expression & Text to see matches. Roll over matches or the expression for details. Undo mistakes with ctrl-z. Save Favorites & Share expressions with friends or the Community. Explore your results with Tools. A full Reference & Help is available in the Library, or watch the video Tutorial. Sample text for testing: abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ 0123456789 _+-.,!@#\$%^&*();\\/|<>"' 12345 -98.7 3.141 .6180 9,000 +42 555.123.4567 +1-(800)-555-2468 foo@demo.net bar.ba@test.co.uk www.demo.com http://foo.co.uk/ http://regexr.com/foo.html?q=bar https://mediatemple.net trans('asd.asd.testword') trans('asddd.asd.asd.testword1') trans('asggfd.asd.asd.asd.asd.testword2') trans('asdrtd.testword3') ((^|, )(part1|part2|part3))+\$`; const subst = `trans('common.$2')`; // The substituted value will be contained in the result variable const result = str.replace(regex, subst); console.log('Substitution result: ', result);

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