Regular Expressions 101

Save & Share

Flavor

  • PCRE2 (PHP >=7.3)
  • PCRE (PHP <7.3)
  • ECMAScript (JavaScript)
  • Python
  • Golang
  • Java 8
  • .NET 7.0 (C#)
  • Rust
  • Regex Flavor Guide

Function

  • Match
  • Substitution
  • List
  • Unit Tests

Tools

Sponsors
There are currently no sponsors. Become a sponsor today!
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 = new RegExp('(?:https?://(?:[\\w-]+\\.)?(?:facebook\\.com|facebookwkhpilnemxj7asaniu7vnjjbiltxjqhye3mhbshg7kx5tfyd\\.onion)/(?:[^#]*?\\#!/)?(?:(?:video/video\\.php|photo\\.php|video\\.php|video/embed|story\\.php|watch(?:/live)?/?)\\?(?:.*?)(?:v|video_id|story_fbid)=|[^/]+/videos/(?:[^/]+/)?|[^/]+/posts/|groups/[^/]+/permalink/|watchparty/)|facebook:)(\\d+)', 'gm') const str = `https://www.facebook.com/video.php?v=637842556329505&fref=nf https://www.facebook.com/video.php?v=274175099429670 https://www.facebook.com/video.php?v=957955867617029 https://www.facebook.com/maxlayn/posts/10153807558977570 https://m.facebook.com/story.php?story_fbid=1035862816472149&id=116132035111903 https://www.facebook.com/barackobama/posts/10153664894881749 https://www.facebook.com/cnn/videos/10155529876156509/ https://www.facebook.com/yaroslav.korpan/videos/1417995061575415/ https://www.facebook.com/LaGuiaDelVaron/posts/1072691702860471 https://www.facebook.com/groups/1024490957622648/permalink/1396382447100162/ https://www.facebook.com/video.php?v=10204634152394104 https://www.facebook.com/amogood/videos/1618742068337349/?fref=nf https://www.facebook.com/ChristyClarkForBC/videos/vb.22819070941/10153870694020942/?type=2&theater facebook:544765982287235 https://www.facebook.com/groups/164828000315060/permalink/764967300301124/ https://zh-hk.facebook.com/peoplespower/videos/1135894589806027/ https://www.facebookwkhpilnemxj7asaniu7vnjjbiltxjqhye3mhbshg7kx5tfyd.onion/video.php?v=274175099429670 https://www.facebook.com/onlycleverentertainment/videos/1947995502095005/ https://www.facebook.com/WatchESLOne/videos/359649331226507/ https://www.facebook.com/100033620354545/videos/106560053808006/ https://www.facebook.com/watch/?v=647537299265662 https://www.facebook.com/PankajShahLondon/posts/10157667649866271 https://m.facebook.com/Alliance.Police.Department/posts/4048563708499330 https://www.facebook.com/groups/ateistiskselskab/permalink/10154930137678856/ https://www.facebook.com/watch/live/?v=1823658634322275 https://www.facebook.com/watchparty/211641140192478`; // 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