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

/
/
g

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 = "(?m)^.*?Exception.*(?:\\R+^\\s*at .*)+"; final String string = " INFO [main] (AutoMain.java:133) - querying data 1\n" + "DEBUG [main] (AutoMain.java:142) - data 1 count: 23180\n" + " INFO [main] (AutoMain.java:151) - querying data 2\n" + "ERROR [main] (AutoMain.java:607) - Failure in auto\n" + "java.net.ConnectException: Connection refused (Connection refused)\n" + " at java.net.PlainSocketImpl.socketConnect(Native Method)\n" + " at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)\n" + " at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)\n" + " at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)\n" + " at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)\n" + " at java.net.Socket.connect(Socket.java:589)\n" + " at java.net.Socket.connect(Socket.java:538)\n" + " at java.net.Socket.<init>(Socket.java:434)\n" + " at java.net.Socket.<init>(Socket.java:211)\n" + " at com.myCompany.client.ClientIOFactory$1.<init>(ClientIOFactory.java:17)\n" + " at com.myCompany.client.ClientIOFactory.lambda$clientIOFactoryFromSocket$0(ClientIOFactory.java:15)\n" + " at com.myCompany.client.queryData(Client.java:83)\n" + " at com.myCompany.client.queryData(Client.java:91)\n" + " at com.myCompany.queryOptData(InstantAutomaton.java:153)\n" + " at com.myCompany.AutoMain.main(InstantAutomaton.java:426)\n"; final Pattern pattern = Pattern.compile(regex); 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