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

~
~
ig

Test String

Code Generator

Language

Generated Code

$re = '~(?:http|https|)(?::\/\/|)(?:www.|)(?:youtu\.be\/|youtube\.com(?:\/embed\/|\/v\/|\/watch\?v=|\/ytscreeningroom\?v=|\/feeds\/api\/videos\/|\/user\S*[^\w\-\s]|\S*[^\w\-\s]))([\w\-]{11})[a-z0-9;:@#?&%=+\/\$_.-]*~i'; $str = 'https://www.youtube.com/watch?v=N0bIBkXKbqI&feature=youtu.be https://youtu.be/PTZI_QGhTlk http://www.youtube.com/watch?v=-wtIMTCHWuI http://www.youtube.com/v/-wtIMTCHWuI?version=3&autohide=1 http://youtu.be/-wtIMTCHWuI http://www.youtube.com/oembed?url=http%3A//www.youtube.com/watch?v%3D-wtIMTCHWuI&format=json https://www.youtube.com/embed/M7lc1UVf-VE # NOT MATCHED http://www.youtube.com/attribution_link?a=JdfC0C9V6ZI&u=%2Fwatch%3Fv%3DEhxJLojIE_o%26feature%3Dshare https://www.youtube.com/attribution_link?a=8g8kPrPIi-ecwIsS&u=/watch%3Fv%3DyZv2daTWRZU%26feature%3Dem-uploademail'; preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0); // Print the entire match result var_dump($matches);

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 PHP, please visit: http://php.net/manual/en/ref.pcre.php