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

/
/
gm

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 = "\\[(?P<severity>\\w+)\\]\\s*(?P<remote>[^\\s:]+):(?P<port>\\d+)\\s*-\\s*(?P<id>\\d+)\\s*\"(?P<type>[\\w]+)\\s*(?P<class>\\w+)\\s*(?P<name>[^\\s]+)\\s*(?P<proto>\\w+)\\s*(?P<size>\\d+)\\s*(?P<do>\\w+)\\s*(?P<bufsize>\\d+)\"\\s*(?P<rcode>\\w+)\\s*(?P<rflags>[^\\s]+)\\s+(?P<rsize>\\d+)\\s*(?P<duration>[^\\s]+)"; final String string = "[INFO] 172.20.164.61:52054 - 29029 \"AAAA IN private-link-api.coralogix.in. udp 47 false 512\" NOERROR qr,aa,rd,ra 163 0.000061739s\n" + "[INFO] 172.20.164.61:52054 - 15579 \"A IN private-link-api.coralogix.in.ap-south-1.compute.internal. udp 75 false 512\" NXDOMAIN qr,aa,rd,ra 190 0.000081757s\n\n" + "[INFO] 172.20.164.61:52054 - 15579 \"A IN private-link-api.coralogix.in.ap-south-1.compute.internal. udp 75 false 512\" NXDOMAIN aa,rd,ra 190 0.000081757s\n\n" + "[INFO] 172.20.160.191:44146 - 254 \\\"A IN secretsmanager.ap-south-1.amazonaws.com. udp 57 false 512\\\" NOERROR qr,aa,rd,ra 222 0.000054345s\\n\",\"time\":\"2023-02-13T12:14:26.928909225Z"; 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