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

/
/
gi

Test String

Substitution

Processing...

Code Generator

Language

Generated Code

const regex = /(\|\s*(logo|image|screenshot|race_logo|track map)\s*=\s*)(File:|Image:)?([^\[\||<\n]*)((\|\s*\d{1,4}px(\?)?|\|\s*thumb))((\|\s*\d{1,4}px(\?)?|\|\s*thumb))?(?(?=\|[A-z]*\s*=)|(?(?=\|(\w*\W*)*)(\|[^\|\n]*)?)?)/gi; // Alternative syntax using RegExp constructor // const regex = new RegExp('(\\|\\s*(logo|image|screenshot|race_logo|track map)\\s*=\\s*)(File:|Image:)?([^\\[\\||<\\n]*)((\\|\\s*\\d{1,4}px(\\?)?|\\|\\s*thumb))((\\|\\s*\\d{1,4}px(\\?)?|\\|\\s*thumb))?(?(?=\\|[A-z]*\\s*=)|(?(?=\\|(\\w*\\W*)*)(\\|[^\\|\\n]*)?)?)', 'gi') const str = `| image = [[File:Central Asia (orthographic projection).svg|200px|Map of Central Asia]] |Image=|150px? }}]] &ndash; [[Template:POTD/2012-06-09|{{POTD texttitle |image=Jack-in-cube solid model, light background.gif |thumb=Jack-in-cube solid model, light background frame.png |size=180 |name = Reggae | Image = File:Bob-Marley.jpg|thumb|231px| | caption = Popular reggae artist [[Bob Marley]] in 1980 {{Infobox officeholder |image = Karenskiy AF 1917.jpg|230px |nationality = Russian {{Infobox officeholder |image = Karenskiy AF 1917.jpg|230px|thumb |nationality = Russian {{Infobox officeholder |image = Karenskiy AF 1917.jpg|thumb |nationality = Russian {{Infobox officeholder |image = Karenskiy AF 1917.jpg|230px|nationality = Russian |country=IND |image= National Highway 2 (India).png|300px|Road map of India with NH 19 highlighted in solid blue color |type=NH |image = File:April 14, 2012 Marquette, Kansas EF4 tornado.JPG|309px {{Infobox football club | clubname = Slovácko | image = Image:1FC Slovacko.png|150px|Logo | fullname = 1. FC Slovácko A.S. | | image = <imagemap> File:Primates - some families.jpg|300px`; const subst = `$1$4`; // 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