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

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<timestamp>\\d{4}-\\d{2}-\\d{2} \\d{2}:\\d{2}:\\d{2},\\d{3}) (?P<level>INFO|ERROR|WARN|TRACE|DEBUG|FATAL)\\s+\\[(?P<firstSquareBrackets>[^\\]]*)]\\s+\\[(?P<secondSquareBrackets>[^\\]]*)]\\s+\\[(?P<thirdSquareBrackets>[^\\]]*)]\\s+\\[(?P<fourthSquareBrackets>[^\\]]*)]\\s+\\[(?P<fifthSquareBrackets>[^\\]]*)] - (?P<textMessage>.*?)(?=\\\\Z|;\\s+|\\n)|(?P<exception>^.+Exception: .+)|(?P<stacktrace>^\\s+at .+)|(^\\s+... \\d+ more)|(^\\s*Caused by:.+)"; final String string = "2018-07-24 00:01:33,711 WARN [r3223r2r3] [] [] [ewqrwerwer] [ewfwefwef] - Failed;\n" + "2018-07-24 00:01:33,712 DEBUG [r3223r2r3] [] [] [ewqrwerwer] [ewfwefwef] - Sample log\n" + "2018-07-24 00:02:33,712 DEBUG [r3223r2r3] [] [] [ewqrwerwer] [ewfwefwef] - Sample log\n" + "2018-07-24 00:20:33,830 DEBUG [r3223r2r3] [] [] [ewqrwerwer] [ewfwefwef] - Sample log\n" + "2018-07-24 00:20:37,731 DEBUG [r3223r2r3] [] [] [3r2r32r] [c.i.s.h.r.i.RssNewsServiceImpl] - 3r232r\n" + "2018-07-24 10:33:45,852 ERROR [r3223r2r3] [fgd] [gr] [reger] [regre] - Sample log\n" + "javax.servlet.ServletException: Something bad happened\n" + " at com.example.myproject.OpenSessionInViewFilter.doFilter(OpenSessionInViewFilter.java:60)\n" + " at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)\n" + " at com.example.myproject.ExceptionHandlerFilter.doFilter(ExceptionHandlerFilter.java:28)\n" + " at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)\n" + " at com.example.myproject.OutputBufferFilter.doFilter(OutputBufferFilter.java:33)\n" + " at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)\n" + " at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)\n" + " at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)\n" + " at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)\n" + " at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)\n" + " at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)\n" + " at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)\n" + " at org.mortbay.jetty.Server.handle(Server.java:326)\n" + " at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)\n" + " at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:943)\n" + " at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:756)\n" + " at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:218)\n" + " at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)\n" + " at org.mortbay.jetty.bio.SocketConnector$Connection.run(SocketConnector.java:228)\n" + " at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)\n" + "Caused by: com.example.myproject.MyProjectServletException\n" + " at com.example.myproject.MyServlet.doPost(MyServlet.java:169)\n" + " at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)\n" + " at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)\n" + " at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)"; 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