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

/
/

Test String

Code Generator

Generated Code

import java.util.regex.Matcher; import java.util.regex.Pattern; public class Example { public static void main(String[] args) { final String regex = ".+@.+\\..+"; final String string = "@\n" + "hi@\n" + "@hola\n" + "@hola.com\n" + "mkyong\n" + "Abc@example.com\n" + "user+mailbox/department=shipping@example.com\n" + "юзер@екзампл.ком\n" + "θσερ@εχαμπλε.ψομ\n" + "伊昭傑@郵件.商務\n" + "\"Joe.\\\\Blow\"@example.com\n" + "\"Fred Bloggs\"@example.com\n" + "hi@\n" + "mkyong@.com.my\n" + "mkyong123@gmail.a\n" + "mkyong123@.com\n" + "mkyong123@.com.com\n" + ".mkyong@mkyong.com\n" + "mkyong()*@gmail.com\n" + "mkyong@%*.com\n" + "mkyong..2002@gmail.com\n" + "mkyong.@gmail.com\n" + "mkyong@mkyong@gmail.com\n" + "mkyong@gmail.com.1a\n" + "\"user1@hotmail.com; user2@gmail.com\"\n" + "\"user1@hotmail.com; user2@gmail.com; user3@company.com\"\n" + "\"User Display Name user3@company.com\"\n" + "\"user4 @company.com\"\n" + "List of Valid Email Addresses\n\n" + "email@example.com\n" + "firstname.lastname@example.com\n" + "email@subdomain.example.com\n" + "firstname+lastname@example.com\n" + "email@123.123.123.123\n" + "email@[123.123.123.123]\n" + "\"email\"@example.com\n" + "1234567890@example.com\n" + "email@example-one.com\n" + "_______@example.com\n" + "email@example.name\n" + "email@example.museum\n" + "email@example.co.jp\n" + "firstname-lastname@example.com\n" + "much.”more\\ unusual”@example.com\n" + "very.unusual.”@”.unusual.com@example.com\n" + "very.”(),:;<>[]”.VERY.”very@\\\\ \"very”.unusual@strange.example.com\n" + "plainaddress\n" + "#@%^%#$@#$@#.com\n" + "@example.com\n" + "Joe Smith <email@example.com>\n" + "email.example.com\n" + "email@example@example.com\n" + ".email@example.com\n" + "email.@example.com\n" + "email..email@example.com\n" + "あいうえお@example.com\n" + "email@example.com (Joe Smith)\n" + "email@example\n" + "email@-example.com\n" + "email@example.web\n" + "email@111.222.333.44444\n" + "email@example..com\n" + "plainaddress\n" + "#@%^%#$@#$@#.com\n" + "”(),:;<>[\\]@example.com\n" + "just”not”right@example.com\n" + "this\\ is\"really\"not\\allowed@example.com\n" + "@example.com\n" + "Joe Smith <email@example.com>\n" + "email.example.com\n" + "email@example@example.com\n" + ".email@example.com\n" + "email.@example.com\n" + "email..email@example.com\n" + "あいうえお@example.com\n" + "email@example.com (Joe Smith)\n" + "email@example\n" + "email@-example.com\n" + "email@example.web\n" + "email@111.222.333.44444\n" + "email@example..com\n" + "Abc..123@example.com\n" + "Abc..123@example.com\n" + "much.”more\\ unusual”@example.com\n" + "very.unusual.”@”.unusual.com@example.com\n" + "very.”(),:;<>[]”.VERY.”very@\\\\ \"very”.unusual@strange.example.com\n" + "email@example.com\n" + "firstname.lastname@example.com\n" + "email@subdomain.example.com\n" + "firstname+lastname@example.com\n" + "email@123.123.123.123\n" + "email@[123.123.123.123]\n" + "\"email\"@example.com\n" + "1234567890@example.com\n" + "email@example-one.com\n" + "_______@example.com\n" + "email@example.name\n" + "email@example.museum\n" + "email@example.co.jp\n" + "firstname-lastname@example.com\n"; final Pattern pattern = Pattern.compile(regex); final Matcher matcher = pattern.matcher(string); if (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