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 = "^(?!^[0-9])(?![0-9][AZ])(?![AZ0-9*]*\\*\\*)(?![AZ0-9*]*\\*[AZ])((?=[AZ0-9]{6})|(?=[AZ0-9*]*\\*))(?![AZ0-9*]*[0-9][A-Z])[AZ0-9*]{1,6}$"; final String string = "^(?![0-9])(?![0-9][AZ])(?![AZ0-9*]*\\*\\*)(?![AZ0-9*]*\\*[AZ0])(?=[AZ0-9*]*\\*)(?![AZ0-9*]*[0-9][A-Z])[AZ0-9*]{1,6}$\n" + "Broken down: \n" + "^(?![0-9])\n" + "(?![0-9][AZ])\n" + "(?![AZ0-9*]*\\*\\*)\n" + "(?![AZ0-9*]*\\*[AZ0])\n" + "(?=[AZ0-9*]*\\*)\n" + "(?![AZ0-9*]*[0-9][A-Z])\n" + "[AZ0-9*]{1,6}$\n\n" + "Check these for patterns\n" + "Following would be valid\n" + "*\n" + "*1\n" + "*1*\n" + "*12345\n" + "A*\n" + "A*2\n" + "A*2*\n" + "A1*3\n" + "A1*3*\n" + "A12*4\n" + "A*2\n" + "A*23\n" + "A*234\n" + "A*2345\n" + "A12*45\n" + "A1234*\n" + "A*2345\n" + "A12*4*\n" + "A*23*5\n" + "A123*5\n" + "*12345\n" + "*1234*\n" + "*1*3*5\n" + "*12*4*\n" + "*1*3*5\n" + "*123*5\n" + "A12345\n\n" + "Examples of invalid entries: <Any ** entry> - <Any * A-Z character> - <Any value longer than 6>\n" + "A1\n" + "A12\n" + "A123\n" + "A1234\n" + "*A1234\n" + "B*\n" + "B1*\n" + "BA*45\n" + "B*2345\n" + "**\n" + "*1A\n" + "*1A1*\n" + "*A2345\n" + "*123456\n" + "1234*\n" + "A\n" + "**12\n" + "*1**\n" + "*1*3**\n" + "*12**\n" + "*1*3*56\n" + "*123**\n" + "*12*45*\n" + "A*23456"; 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