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

Code Generator

Language

Generated Code

use strict; my $str = 'https://www.youtube.com/watch?v=-SXKV0jDxuA https://www.youtube.com/watch?v=ylfhCpi9AEU 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 http://i2.ytimg.com/vi/-wtIMTCHWuI/hqdefault.jpg http://youtu.be/zc0s358b3Ys http://www.youtube.com/embed/zc0s358b3Ys http://www.youtube.com/watch?v=zc0s358b3Ys http://www.youtube.com/v/ZTUVgYoeN_b?f=gdata_standard https://www.youtube.com/embed/WVZpCdHq3Qg http://www.youtube.com/watch?argv=xyz&v=u8nQa1cJyX8 http://www.youtube.com/watch?v=0zM3nApSvMg&feature=feedrec_grec_index http://www.youtube.com/user/IngridMichaelsonVEVO#p/a/u/1/QdK8U-VIH_o http://www.youtube.com/v/0zM3nApSvMg?fs=1&amp;hl=en_US&amp;rel=0 http://www.youtube.com/watch?v=0zM3nApSvMg#t=0m10s http://www.youtube.com/embed/0zM3nApSvMg?rel=0 http://www.youtube.com/watch?v=0zM3nApSvMg http://youtu.be/0zM3nApSvMg youtube.com/shared?ci=MZZ02_0O6GQ //www.youtube-nocookie.com/embed/up_lNV-yoK4?rel=0 http://www.youtube.com/user/Scobleizer#p/u/1/1p3vcRhsYGo http://www.youtube.com/watch?v=cKZDdG9FTKY&feature=channel http://www.youtube.com/watch?v=yZ-K7nCVnBI&playnext_from=TL&videos=osPknwzXEas&feature=sub http://www.youtube.com/ytscreeningroom?v=NRHVzbJVx8I http://www.youtube.com/user/SilkRoadTheatre#p/a/u/2/6dwqZw0j_jY http://youtu.be/6dwqZw0j_jY http://www.youtube.com/watch?v=6dwqZw0j_jY&feature=youtu.be http://youtu.be/afa-5HQHiAs http://www.youtube.com/user/Scobleizer#p/u/1/1p3vcRhsYGo?rel=0 http://www.youtube.com/watch?v=cKZDdG9FTKY&feature=channel http://www.youtube.com/watch?v=yZ-K7nCVnBI&playnext_from=TL&videos=osPknwzXEas&feature=sub http://www.youtube.com/ytscreeningroom?v=NRHVzbJVx8I http://www.youtube.com/embed/nas1rJpm7wY?rel=0 http://www.youtube.com/watch?v=peFZbP64dsU http://youtube.com/v/dQw4w9WgXcQ?feature=youtube_gdata_player http://youtube.com/vi/dQw4w9WgXcQ?feature=youtube_gdata_player http://youtube.com/?v=dQw4w9WgXcQ&feature=youtube_gdata_player http://www.youtube.com/watch?v=dQw4w9WgXcQ&feature=youtube_gdata_player http://youtube.com/?vi=dQw4w9WgXcQ&feature=youtube_gdata_player http://youtube.com/watch?v=dQw4w9WgXcQ&feature=youtube_gdata_player http://youtube.com/watch?vi=dQw4w9WgXcQ&feature=youtube_gdata_player http://youtu.be/dQw4w9WgXcQ?feature=youtube_gdata_player https://www.youtube.com/watch?v=UzRtrjyDwx0 https://youtu.be/6butf1tEVKs?t=22s https://youtu.be/R46-XgqXkzE?t=2m52s http://youtu.be/dQw4w9WgXcQ http://www.youtube.com/?v=dQw4w9WgXcQ http://www.youtube.com/?v=dQw4w9WgXcQ&feature=player_embedded http://www.youtube.com/watch?v=dQw4w9WgXcQ http://www.youtube.com/watch?v=dQw4w9WgXcQ&feature=player_embedded http://www.youtube.com/v/dQw4w9WgXcQ http://www.youtube.com/e/dQw4w9WgXcQ http://www.youtube.com/embed/dQw4w9WgXcQ'; my $regex = qr~(?:[/?&](?:e|vi?|ci)(?:[/=]|%3D)|youtu\.be/|embed/|/user/[^/]+#p/(?:[^/]+/)+)\K[\w-]{10,12}~p; if ( $str =~ /$regex/g ) { print "Whole match is ${^MATCH} and its start/end positions can be obtained via \$-[0] and \$+[0]\n"; # print "Capture Group 1 is $1 and its start/end positions can be obtained via \$-[1] and \$+[1]\n"; # print "Capture Group 2 is $2 ... and so on\n"; } # ${^POSTMATCH} and ${^PREMATCH} are also available with the use of '/p' # Named capture groups can be called via $+{name}

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 Perl, please visit: http://perldoc.perl.org/perlre.html