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

/
/
gms

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 = "System Message: (?<agent>\\w+) is ready to chat.*?[\\r\\n]+[\\d\\/]+\\s+[\\d:]+\\s+\\w+\\s+[\\r\\n]+(?P=agent)[\\r\\n]+(?<agentFirstResponse>.*?)[\\r\\n]+[\\d\\/]+\\s+[\\d:]+\\s+\\w+"; final String string = "1/1/2019 2:42:55 AM \n" + "Aju \n" + "Hi Team\n\n" + "1/1/2019 2:42:56 AM \n" + "System \n" + "The data has been added: \n" + "- Customer Info\n\n" + "1/1/2019 2:42:59 AM \n" + "Rohi\n" + "System Message: Rohi is ready to chat. \n\n" + "1/1/2019 2:43:09 AM \n" + "Aju \n" + "Wish you a very happy ne year \n\n" + "1/1/2019 2:43:12 AM \n" + "Aju \n" + "new* \n\n" + "1/1/2019 2:43:25 AM \n" + "Aju \n" + "I need to KNOW ABOUT A CAR\n\n" + "1/1/2019 2:43:32 AM \n" + "Aju \n" + "please help me \n\n" + "1/1/2019 2:45:07 AM \n" + "Aju \n" + "Anyone there ? \n\n" + "1/1/2019 2:47:13 AM \n" + "Aju \n" + "?? \n\n" + "1/1/2019 2:49:23 AM \n" + "Aju \n" + "?? Hi Rohi You there? \n\n" + "1/1/2019 2:51:16 AM \n" + "Rohi\n" + "Hello Aju my name is Rohi. How can I help you today? \n\n" + "1/1/2019 2:51:27 AM\n\n" + "Chat goes on...."; final Pattern pattern = Pattern.compile(regex, Pattern.MULTILINE | Pattern.DOTALL); 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