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 = "(?<FieldA>WARN)\\s+\\[(?<FieldB>[^\\]]*)\\]\\s+\\[(?<FieldC>[^\\]]*)\\]\\s+(?<FieldD>log)\\s(?<FieldE>\\d{4}-\\d{2}-\\d{2}\\s\\d{2}:\\d{2}:\\d{2}.\\d{3})\\s(?<FieldF>.*):\\s+(?<MessageText>.*)$"; final String string = "2014-05-11 18:24:05,957 WARN [Logger@9233091 3.3.1/389] [Coherence] log 2014-05-11 18:24:05.957 Oracle Coherence GE 3.3.1/389 (thread=PacketPublisher, member=2): A potential communication problem ...the same cluster member (Member(Id=1, Timestamp=2014-05-11 18:17:48.519, Address=xxx.xxx.xxx.x:8090, MachineId=12345, Location=process:1234@CONFLUENCE01)) to this member (Member(Id=2, Timestamp=2014-05-11 18:23:16.19, Address=xxx.xxx.xxx.x:8090, MachineId=67891, Location=process:1234@CONFLUENCE02)) as recently as 0 ... and unreasonably lengthy GC times.\n\n" + "2014-05-11 18:13:49,218 WARN [Logger@9226875 3.3.1/389] [Coherence] log 2014-05-11 18:13:49.218 Oracle Coherence GE 3.3.1/389 (thread=PacketPublisher, member=2): Timeout while delivering a packet; the member appears to be alive, but exhibits long periods of unresponsiveness; removing Member(Id=1, Timestamp=2014-05-11 18:09:52.641, Address=xxx.xxx.xxx.x:8090, MachineId=41352, Location=process:1234@CONFLUENCE01)\n\n" + "2014-05-11 18:13:49,249 INFO [Cluster:EventDispatcher] [confluence.cluster.coherence.TangosolClusterManager] memberLeft Member has left cluster: Member(Id=1, Timestamp=2014-05-11 18:13:49.218, Address=xxx.xxx.xxx.x:8090, MachineId=12345, Location=process:1234@CONFLUENCE01) \n\n" + "2014-05-11 18:13:49,436 WARN [Logger@9226875 3.3.1/389] [Coherence] log 2014-05-11 18:13:49.436 Oracle Coherence GE 3.3.1/389 (thread=Cluster, member=2): The member formerly known as Member(Id=1, Timestamp=2014-05-11 18:13:49.218, Address=xxx.xxx.xxx.x:8090, MachineId=12345, Location=process:1234@CONFLUENCE01) has been forcefully evicted from the cluster, but continues to emit a cluster heartbeat; henceforth, the member will be shunned and its messages will be ignored."; 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