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]
  • Character class intersection
    [\w&&[^\d]]
  • 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
Processing...

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 = "(?:[a-z0-9+!#$%&'*+/=?^_`\\{|\\}~-]+(?:\\.[a-z0-9!#$%&'*+/=?^_`\\{|\\}~-]+)*|\"(?:[\\x01-\\x08\\x0b\\x0c\\x0e-\\x1f\\x21\\x23-\\x5b\\x5d-\\x7f]|\\\\[\\x01-\\x09\\x0b\\x0c\\x0e-\\x7f])*\")@(?:(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?|\\[(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?|[a-z0-9-]*[a-z0-9]:(?:[\\x01-\\x08\\x0b\\x0c\\x0e-\\x1f\\x21-\\x5a\\x53-\\x7f]|\\\\[\\x01-\\x09\\x0b\\x0c\\x0e-\\x7f])+)\\])"; final String string = "[a-zA-Z0-9-_.+]+@[a-zA-Z0-9-_.]+\n\n" + "ekoprasetyo.crb@outlook.com\n" + "db.maulana@gmail.com.\n" + " dee.wien@yahoo.com. .\n" + "\"deninainggolan@yahoo.co.id\" \n" + "Fajar.rohita@hotmail.com klaas knot (firmansya1404@gmail.aero); \n" + "dydmm, sss <fransisca+jw@gmail.com>, donny_tri_wardono@yahoo.co.id thank a\n" + "\"Helpdesk | Energiem**ine\" <helpdesk@ene---ine.nl>\n" + "invalid: John..Doe@example.com \n" + "valid: John.Doe@example.com\n\n" + "Valid addresses from https://en.wikipedia.org/wiki/Email_address\n" + "simple@example.com\n" + "very.common@example.com\n" + "FirstName.LastName@EasierReading.org\n" + "x@example.com\n" + "long.email-address-with-hyphens@and.subdomains.example.com\n" + "user.name+tag+sorting@example.com\n" + "name/surname@example.com\n" + "admin@example\n" + "example@s.example\n" + "\" \"@example.org\n" + "\"john..doe\"@example.org\n" + "mailhost!username@example.org\n" + "\"very.(),:;<>[]\\\".VERY.\\\"very@\\\\ \\\"very\\\".unusual\"@strange.example.com\n" + "user%example.com@example.org\n" + "user-@example.org\n" + "postmaster@[123.123.123.123]\n" + "postmaster@[IPv6:2001:0db8:85a3:0000:0000:8a2e:0370:7334]\n" + "_test@[IPv6:2001:0db8:85a3:0000:0000:8a2e:0370:7334]"; final Pattern pattern = Pattern.compile(regex, Pattern.CASE_INSENSITIVE); 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