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

/
/
gm

Test String

Code Generator

Language

Generated Code

using System; using System.Text.RegularExpressions; public class Example { public static void Main() { string pattern = @"^https?:\/\/(?:(?:(?:www\.)?youtu(?:(?:be\.(?:com|nl|it|co\.nz|com\.br|de|es|ru))|(?:be-nocookie\.com))\/(?:(?:watch\?v=)|(?:v\/)|(?:embed\/)))|(?:youtu\.be\/))(?<video_id>[a-zA-Z0-9\-_]{11})(?:[a-zA-Z0-9\-_\?=&%\.]+)?$"; string input = @"https://www.youtube.com/watch?v=Cf_4WmACpws https://www.youtube.com/watch?v=oXXiJx7kaeE https://youtu.be/Cf_4WmACpws?t=6879 https://www.youtube.com/watch?v=xYXV-SysdLw https://www.youtube.nl/watch?v=xYXV-SysdLw https://youtu.be/xYXV-SysdLw https://www.youtube.com/channel/UClgRkhTL3_hImCAmdLfDE4g https://www.youtube.com/feed/trending https://youtu.be/YV-5SqpjBII&derp=%3Dhttps.comsfsdf https://www.youtube.com/watch?v=6E3MMKzBn1g https://www.youtube.com/feed/history http://www.youtube.com/playlist?list=WL https://www.youtube.com/watch?v=0f1cRNmQHVE https://www.youtube.com/playlist?list=PLK8KId9LS-dRgDGDNLgMqBRXlwbUAuF0s https://www.youtube.com/channel/UCFbNIlppjAuEX4znoulh0Cw https://www.youtube.com/embed/M7lc1UVf-VE 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 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://s.ytimg.com/yt/favicon-wtIMTCHWuI.ico http://i2.ytimg.com/vi/-wtIMTCHWuI/hqdefault.jpg https://www.youtube-nocookie.com/watch?v=Cf_4WmACpws https://www.youtube.com/watch?v=inu0xeteuxg"; RegexOptions options = RegexOptions.Multiline; foreach (Match m in Regex.Matches(input, pattern, options)) { Console.WriteLine("'{0}' found at index {1}.", m.Value, m.Index); } } }

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 C#, please visit: https://msdn.microsoft.com/en-us/library/system.text.regularexpressions.regex(v=vs.110).aspx