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

/
/
gmx

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 = "(?# This regex was created for the purposes of detecting potentially compromised credentials for the purposes of information security and not to be used for malicious purposes.)\n" + "(?<!\\d)\n" + "(?# s - Short [less than 16 digits], m - Medium [16 digits], l - Long [more than 16 digits; not yet implemented])\n" + "(?# First four digits)\n" + "(?:\n" + " (?# Standard 16 digit numbers)\n" + " (?<m>\n" + " (?#MasterCard between 222100-272099)\n" + " 222[1-9]|223\\d|2[3-6]\\d{2}|27[01]\\d|2720|\n" + " (?#JCB is between 3528-3589)\n" + " 352[89]|35[3-8]\\d|\n" + " (?#Visa, MasterCard, Discover)\n" + " [4-6]\\d{3}\n" + " )|\n" + " (?#American Express 15 digits | Diners Club 14 digits)\n" + " (?<s>(?<ax>3[47]\\d{2})|(?<dc>30[0-5]\\d|36\\d{2}))\n" + ")\n" + "(?# Rest of the card number)\n" + "(?<del>\\D+)?(?(<m>)\\d{4}(?(<del>)\\k\\{del\\})\\d{4}(?(<del>)\\k\\{del\\})\\d{4}|(?:\\d{6})(?(<del>)\\k\\{del\\})(?(<ax>)\\d{5}|\\d{4}))\n" + "(?#END)\n" + "(?!\\d)"; final String string = "# Based on data from https://www.freeformatter.com/credit-card-number-generator-validator.html\n\n" + "# Currently only works for Visa, MasterCard, Discover, AmEx, JCB, Diners Club and only 16 digits (15 for AmEx, 14 for Diners Club Int'l)\n\n" + "# VISA:\n" + "4600259666104540\n" + "4556-1328-5230-3974\n" + "4485733989514555546\n" + "# MasterCard:\n" + "5288718104904007\n" + "5183-2272-0427-5165\n" + "2221001473307772\n" + "# American Express (AMEX):\n" + "379094106835131\n" + "3767-607295-33484\n" + "345614253532917\n" + "# Discover:\n" + "6011277600566135\n" + "6011-7825-5703-7196\n" + "6011621290066569622\n" + "# JCB:\n" + "3542928645179210\n" + "3538837785961400\n" + "3540948375054149466\n" + "# Diners Club - North America:\n" + "5440569380986811\n" + "5500771351399605\n" + "5555244536769443\n" + "# Diners Club - Carte Blanche:\n" + "30360146296936\n" + "30381212693491\n" + "30178078889506\n" + "# Diners Club - International:\n" + "36760821695498\n" + "36861772048826\n" + "36442207191455\n" + "# Maestro:\n" + "6759789245430267\n" + "5893000324731008\n" + "5038101669768864\n" + "# Visa Electron:\n" + "4026108950062250\n" + "4913708902962931\n" + "4844361267840716\n" + "# InstaPayment:\n" + "6370603085892230\n" + "6390038329060763\n" + "6395957073920994"; final Pattern pattern = Pattern.compile(regex, Pattern.MULTILINE | Pattern.COMMENTS); 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