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

~
~
mg

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 = "(?:^|\\W)(?:youtube(?:-nocookie)?\\.com/(?:.*[?&]v=|v/|e(?:mbed)?/|[^/]+/.+/)|youtu\\.be/)([\\w-]+)"; final String string = "youtube.com/watch?v=DFYRQ_zQ-gk\n" + "www.youtube.com/watch?v=DFYRQ_zQ-gk\n" + "https://youtube.com/watch?v=DFYRQ_zQ-gk\n" + "https://www.youtube.com/watch?v=DFYRQ_zQ-gk\n" + "https://www.youtube.com/watch?v=DFYRQ_zQ-gk&feature=feedrec_grec_index\n" + "https://www.youtube.com/watch?v=DFYRQ_zQ-gk#t=0m10s\n" + "https://www.youtube.com/?feature=player_embedded&v=DFYRQ_zQ-gk\n" + "https://www.youtube.com/watch?feature=player_embedded&v=DFYRQ_zQ-gk\n" + "https://www.youtube.com/UCucW7UIJh8FHbv2O0jW8skw?v=DFYRQ_zQ-gk#t=0m10s\n\n" + "https://www.youtube.com/v/DFYRQ_zQ-gk?fs=1&amp;hl=en_US&amp;rel=0\n" + "https://www.youtube.com/e/DFYRQ_zQ-gk?fs=1&amp;hl=en_US&amp;rel=0\n" + "https://www.youtube.com/embed/DFYRQ_zQ-gk?rel=0\n" + "https://www.youtube.com/user/UCucW7UIJh8FHbv2O0jW8skw#p/u/11/DFYRQ_zQ-gk?rel=0\n" + "https://www.youtube.com/UCucW7UIJh8FHbv2O0jW8skw#p/c/54B8C800269D7C1B/0/DFYRQ_zQ-gk?rel=0\n\n" + "m.youtube.com/watch?v=DFYRQ_zQ-gk\n" + "//m.youtube.com/watch?v=DFYRQ_zQ-gk\n" + "https://m.youtube.com/watch?v=DFYRQ_zQ-gk\n\n" + "youtu.be/DFYRQ_zQ-gk\n" + "https://youtu.be/DFYRQ_zQ-gk\n" + "https://youtu.be/DFYRQ_zQ-gk?t=2s\n" + "https://youtu.be/DFYRQ_zQ-gk?list=PLelYX5BVrtO0sWvnTSdvot21pjlKTNVeU\n\n" + "https://youtube-nocookie.com/watch?v=DFYRQ_zQ-gk?t=2s\n\n" + "<iframe width=\"480\" height=\"270\" src=\"https://www.youtube.com/embed/DFYRQ_zQ-gk?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture\" allowfullscreen></iframe>\n\n" + "in text youtube.com/watch?v=DFYRQ_zQ-gk in text\n\n" + "DFYRQ_zQ-gk\n" + "/watch?v=DFYRQ_zQ-gk\n" + "https://www.youtubee.com/watch?v=DFYRQ_zQ-gk\n" + "https://notyoutube.com/watch?v=DFYRQ_zQ-gk\n"; final Pattern pattern = Pattern.compile(regex, Pattern.MULTILINE); 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