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

/
/
ig

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\n\n\n\n\n" + "# Hello 54.217.223.119. Your session has been logged.<br />\n" + "#<br />\n" + "# Copyright (c) 2002 - 2014 by DK Hostmaster A/S<br />\n" + "# <br />\n" + "# The data in the DK Whois database is provided by DK Hostmaster A/S<br />\n" + "# for information purposes only, and to assist persons in obtaining<br />\n" + "# information about or related to a domain name registration record.<br />\n" + "# We do not guarantee its accuracy. We will reserve the right to remove<br />\n" + "# access for entities abusing the data, without notice.<br />\n" + "# <br />\n" + "# Any use of this material to target advertising or similar activities<br />\n" + "# are explicitly forbidden and will be prosecuted. DK Hostmaster A/S<br />\n" + "# requests to be notified of any such activities or suspicions thereof.<br />\n" + "Domain: dr.dk<br />\n" + "DNS: dr.dk<br />\n" + "Registered: 1998-03-11<br />\n" + "Expires: 2015-03-31<br />\n" + "Registration period: 1 year<br />\n" + "VID: no<br />\n" + "Status: Active<br />\n" + "Registrant<br />\n" + "Handle: D5109-DK<br />\n" + "Name: DR<br />\n" + "Address: DR-Byen, Emil Holms kanal 20<br />\n" + "Postalcode: 0999<br />\n" + "City: København C<br />\n" + "Country: DK<br />\n" + "Phone: +4535203661<br />\n" + "Administrator<br />\n" + "Handle: DH4991-DK<br />\n" + "Name: DR<br />\n" + "Attention: DR Hostmaster<br />\n" + "Address: DR-Byen, Emil Holms kanal 20<br />\n" + "Postalcode: 0999<br />\n" + "City: København C<br />\n" + "Country: DK<br />\n" + "Phone: +4535203660<br />\n" + "Nameservers<br />\n" + "Hostname: dns101.telia.com<br />\n" + "Handle: TA632-DK<br />\n" + "Hostname: dns102.telia.com<br />\n" + "Handle: TA632-DK<br />\n" + "Hostname: ns01.dr.dk<br />\n" + "Handle: DR3450-DK<br />"; 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