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

/
/
gs

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 = "<%.*?%>"; final String string = "<%@ page import=\"java.io.*,java.util.*\" %>\n" + "<html>\n" + " <head>\n" + " <title>Auto Refresh</title>\n" + " </head>\n" + " <body>\n" + " <fieldset style=\"width:20%; background-color:#e6ffe6;\">\n" + " <legend>Auto refresh</legend>\n" + " <h2>Auto Refresh Example</h2>\n" + " <%\n" + " // Set refresh, autoload time as 1 seconds\n" + " response.setIntHeader(\"Refresh\", 1);\n" + " // Get current time\n" + " Calendar calendar = new GregorianCalendar();\n" + " String am_pm;\n" + " int hour = calendar.get(Calendar.HOUR);\n" + " int minute = calendar.get(Calendar.MINUTE);\n" + " int second = calendar.get(Calendar.SECOND);\n" + " if(calendar.get(Calendar.AM_PM) == 0)\n" + " am_pm = \"AM\";\n" + " else\n" + " am_pm = \"PM\";\n" + " String CT = hour+\":\"+ minute +\":\"+ second +\" \"+ am_pm;\n" + " out.println(\"Crrent Time: \" + CT + \"\\n\");\n" + " %>\n" + " </fieldset>\n" + " </body>\n" + "</html>"; final Pattern pattern = Pattern.compile(regex, 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