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

r"
"
gm

Test String

Substitution

Processing...

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 = "([0-9A-F]{2}:){5}[0-9A-F]{2}"; final String string = "[DHCP IP: (192.168.1.17)] to MAC address 00:50:8D:91:40:A3, Monday, Aug 10,2020 21:06:09\n" + "[DHCP IP: (192.168.1.11)] to MAC address 00:FA:21:46:F0:70, Monday, Aug 10,2020 19:41:28\n" + "[DHCP IP: (192.168.1.14)] to MAC address 8C:79:67:C1:C4:F7, Monday, Aug 10,2020 19:41:12\n" + "[DHCP IP: (192.168.1.7)] to MAC address 00:1C:C0:F0:8A:94, Monday, Aug 10,2020 16:51:41\n" + "[DHCP IP: (192.168.1.17)] to MAC address 00:50:8D:91:40:A3, Monday, Aug 10,2020 15:53:03\n" + "[DHCP IP: (192.168.1.12)] to MAC address 0C:62:A6:E4:60:A6, Monday, Aug 10,2020 15:48:05\n" + "[Dynamic DNS] host name 520techsec.hopto.org registration successful, Monday, Aug 10,2020 14:29:55\n" + "[Dynamic DNS] host name 520techsec.hopto.org registration failure, Monday, Aug 10,2020 14:29:24\n" + "[Dynamic DNS] host name 520techsec.hopto.org registration failure, Monday, Aug 10,2020 14:28:53\n" + "[Dynamic DNS] host name 520techsec.hopto.org registration failure, Monday, Aug 10,2020 14:28:22\n" + "[DHCP IP: (192.168.1.10)] to MAC address 6C:C2:17:1E:B4:B9, Monday, Aug 10,2020 09:51:03\n" + "[DHCP IP: (192.168.1.17)] to MAC address 00:50:8D:91:40:A3, Monday, Aug 10,2020 09:04:50\n" + "[DHCP IP: (192.168.1.11)] to MAC address 00:FA:21:46:F0:70, Monday, Aug 10,2020 08:10:16\n" + "[DHCP IP: (192.168.1.14)] to MAC address 8C:79:67:C1:C4:F7, Monday, Aug 10,2020 08:10:01\n" + "[DHCP IP: (192.168.1.13)] to MAC address 00:16:44:DF:C7:92, Monday, Aug 10,2020 07:11:22\n" + "[DHCP IP: (192.168.1.13)] to MAC address 00:16:44:DF:C7:92, Monday, Aug 10,2020 07:04:23\n" + "[DHCP IP: (192.168.1.7)] to MAC address 00:1C:C0:F0:8A:94, Monday, Aug 10,2020 04:51:42\n" + "[DHCP IP: (192.168.1.17)] to MAC address 00:50:8D:91:40:A3, Monday, Aug 10,2020 03:52:41\n" + "[DHCP IP: (192.168.1.12)] to MAC address 0C:62:A6:E4:60:A6, Monday, Aug 10,2020 03:48:20\n" + "[DHCP IP: (192.168.1.10)] to MAC address 6C:C2:17:1E:B4:B9, Sunday, Aug 09,2020 21:15:05\n" + "[DHCP IP: (192.168.1.17)] to MAC address 00:50:8D:91:40:A3, Sunday, Aug 09,2020 21:06:42\n" + "[DHCP IP: (192.168.1.8)] to MAC address 9C:B6:D0:73:52:AB, Sunday, Aug 09,2020 20:53:45\n" + "[DHCP IP: (192.168.1.11)] to MAC address 00:FA:21:46:F0:70, Sunday, Aug 09,2020 20:39:03\n" + "[DHCP IP: (192.168.1.14)] to MAC address 8C:79:67:C1:C4:F7, Sunday, Aug 09,2020 20:38:48\n" + "[DHCP IP: (192.168.1.8)] to MAC address 9C:B6:D0:73:52:AB, Sunday, Aug 09,2020 20:33:15\n" + "[DHCP IP: (192.168.1.7)] to MAC address 00:1C:C0:F0:8A:94, Sunday, Aug 09,2020 16:51:41\n" + "[DHCP IP: (192.168.1.17)] to MAC address 00:50:8D:91:40:A3, Sunday, Aug 09,2020 15:53:06\n" + "[DHCP IP: (192.168.1.12)] to MAC address 0C:62:A6:E4:60:A6, Sunday, Aug 09,2020 15:48:33\n" + "[Dynamic DNS] host name 520techsec.hopto.org registration successful, Sunday, Aug 09,2020 14:28:12\n" + "[Dynamic DNS] host name 520techsec.hopto.org registration failure, Sunday, Aug 09,2020 14:27:41\n" + "[Dynamic DNS] host name 520techsec.hopto.org registration failure, Sunday, Aug 09,2020 14:27:10\n" + "[Dynamic DNS] host name 520techsec.hopto.org registration failure, Sunday, Aug 09,2020 14:26:38\n" + "[DHCP IP: (192.168.1.11)] to MAC address 00:FA:21:46:F0:70, Sunday, Aug 09,2020 09:07:51\n" + "[DHCP IP: (192.168.1.14)] to MAC address 8C:79:67:C1:C4:F7, Sunday, Aug 09,2020 09:07:37\n" + "[DHCP IP: (192.168.1.17)] to MAC address 00:50:8D:91:40:A3, Sunday, Aug 09,2020 09:05:37"; final String subst = ""; final Pattern pattern = Pattern.compile(regex, Pattern.MULTILINE); final Matcher matcher = pattern.matcher(string); // The substituted value will be contained in the result variable final String result = matcher.replaceAll(subst); System.out.println("Substitution result: " + result); } }

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