Regular Expressions 101

Save & Share

  • Regex Version: ver. 1
  • Update Regex
    ctrl+⇧+s
  • Save new Regex
    ctrl+s
  • Add to Community Library

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

~
~
g

Test String

Code Generator

Language

Generated Code

import java.util.regex.Matcher; import java.util.regex.Pattern; public class Example { public static void main(String[] args) { final String regex = "(?:[/?&](?:e|vi?|ci)(?:[/=]|%3D)|youtu\\.be/|embed/|/user/[^/]+#p/(?:[^/]+/)+)\\K[\\w-]{10,12}"; final String string = "https://www.youtube.com/watch?v=-SXKV0jDxuA\n" + "https://www.youtube.com/watch?v=ylfhCpi9AEU\n" + "http://www.youtube.com/watch?v=-wtIMTCHWuI\n" + "http://www.youtube.com/v/-wtIMTCHWuI?version=3&autohide=1\n" + "http://youtu.be/-wtIMTCHWuI\n" + "http://www.youtube.com/oembed?url=http%3A//www.youtube.com/watch?v%3D-wtIMTCHWuI&format=json\n" + "http://i2.ytimg.com/vi/-wtIMTCHWuI/hqdefault.jpg\n" + "http://youtu.be/zc0s358b3Ys\n" + "http://www.youtube.com/embed/zc0s358b3Ys\n" + "http://www.youtube.com/watch?v=zc0s358b3Ys\n" + "http://www.youtube.com/v/ZTUVgYoeN_b?f=gdata_standard\n" + "https://www.youtube.com/embed/WVZpCdHq3Qg\n" + "http://www.youtube.com/watch?argv=xyz&v=u8nQa1cJyX8\n" + "http://www.youtube.com/watch?v=0zM3nApSvMg&feature=feedrec_grec_index\n" + "http://www.youtube.com/user/IngridMichaelsonVEVO#p/a/u/1/QdK8U-VIH_o\n" + "http://www.youtube.com/v/0zM3nApSvMg?fs=1&amp;hl=en_US&amp;rel=0\n" + "http://www.youtube.com/watch?v=0zM3nApSvMg#t=0m10s\n" + "http://www.youtube.com/embed/0zM3nApSvMg?rel=0\n" + "http://www.youtube.com/watch?v=0zM3nApSvMg\n" + "http://youtu.be/0zM3nApSvMg\n" + "youtube.com/shared?ci=MZZ02_0O6GQ\n" + "//www.youtube-nocookie.com/embed/up_lNV-yoK4?rel=0\n" + "http://www.youtube.com/user/Scobleizer#p/u/1/1p3vcRhsYGo\n" + "http://www.youtube.com/watch?v=cKZDdG9FTKY&feature=channel\n" + "http://www.youtube.com/watch?v=yZ-K7nCVnBI&playnext_from=TL&videos=osPknwzXEas&feature=sub\n" + "http://www.youtube.com/ytscreeningroom?v=NRHVzbJVx8I\n" + "http://www.youtube.com/user/SilkRoadTheatre#p/a/u/2/6dwqZw0j_jY\n" + "http://youtu.be/6dwqZw0j_jY\n" + "http://www.youtube.com/watch?v=6dwqZw0j_jY&feature=youtu.be\n" + "http://youtu.be/afa-5HQHiAs\n" + "http://www.youtube.com/user/Scobleizer#p/u/1/1p3vcRhsYGo?rel=0\n" + "http://www.youtube.com/watch?v=cKZDdG9FTKY&feature=channel\n" + "http://www.youtube.com/watch?v=yZ-K7nCVnBI&playnext_from=TL&videos=osPknwzXEas&feature=sub\n" + "http://www.youtube.com/ytscreeningroom?v=NRHVzbJVx8I\n" + "http://www.youtube.com/embed/nas1rJpm7wY?rel=0\n" + "http://www.youtube.com/watch?v=peFZbP64dsU\n" + "http://youtube.com/v/dQw4w9WgXcQ?feature=youtube_gdata_player\n" + "http://youtube.com/vi/dQw4w9WgXcQ?feature=youtube_gdata_player\n" + "http://youtube.com/?v=dQw4w9WgXcQ&feature=youtube_gdata_player\n" + "http://www.youtube.com/watch?v=dQw4w9WgXcQ&feature=youtube_gdata_player\n" + "http://youtube.com/?vi=dQw4w9WgXcQ&feature=youtube_gdata_player\n" + "http://youtube.com/watch?v=dQw4w9WgXcQ&feature=youtube_gdata_player\n" + "http://youtube.com/watch?vi=dQw4w9WgXcQ&feature=youtube_gdata_player\n" + "http://youtu.be/dQw4w9WgXcQ?feature=youtube_gdata_player\n" + "https://www.youtube.com/watch?v=UzRtrjyDwx0\n" + "https://youtu.be/6butf1tEVKs?t=22s\n" + "https://youtu.be/R46-XgqXkzE?t=2m52s\n" + "http://youtu.be/dQw4w9WgXcQ\n" + "http://www.youtube.com/?v=dQw4w9WgXcQ\n" + "http://www.youtube.com/?v=dQw4w9WgXcQ&feature=player_embedded\n" + "http://www.youtube.com/watch?v=dQw4w9WgXcQ\n" + "http://www.youtube.com/watch?v=dQw4w9WgXcQ&feature=player_embedded\n" + "http://www.youtube.com/v/dQw4w9WgXcQ\n" + "http://www.youtube.com/e/dQw4w9WgXcQ\n" + "http://www.youtube.com/embed/dQw4w9WgXcQ"; final Pattern pattern = Pattern.compile(regex); final Matcher matcher = pattern.matcher(string); while (matcher.find()) { System.out.println("Full match: " + matcher.group(0)); for (int i = 1; i <= matcher.groupCount(); i++) { System.out.println("Group " + i + ": " + matcher.group(i)); } } } }

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 Java, please visit: https://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html