Regular Expressions 101

Save & Share

Flavor

  • PCRE2 (PHP >=7.3)
  • PCRE (PHP <7.3)
  • ECMAScript (JavaScript)
  • Python
  • Golang
  • Java 8
  • .NET 7.0 (C#)
  • Rust
  • Regex Flavor Guide

Function

  • Match
  • Substitution
  • List
  • Unit Tests

Tools

Sponsors
There are currently no sponsors. Become a sponsor today!
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 = "(?!(\\d){3}(-| |)\\1{2}\\2\\1{4})(?!666|000|9\\d{2})(\\b\\d{3}(-| |)(?!00)\\d{2}\\4(?!0{4})\\d{4}\\b)"; final String string = "################\n" + "## Must match:\n" + "################\n\n" + "123-45-4891\n" + "098-18-6564\n" + "123-45-4848\n" + "702-02-0202\n" + "001-14-0004\n" + "009958881\n" + "078-05-1120\n" + "009 95 8881\n" + "123-45-4891 is my ssn\n" + "my ssn is 123-45-4891\n" + "my ssn is 123-45-4891 ok?\n" + "my ssn is 123-45-4891.\n" + "123454891 is my ssn\n" + "my ssn is 123454891\n" + "my ssn is 123454891 ok?\n" + "my ssn is 123454891.\n" + "123 45 4891 is my ssn\n" + "my ssn is 123 45 4891\n" + "my ssn is 123 45 4891 ok?\n" + "my ssn is 123 45 4891.\n" + "my ssn is:123-45-4891.\n" + "my ssn is:123 45 4891.\n" + "my ssn is:123454891.\n\n" + "################\n" + "## Must not match:\n" + "################\n\n" + "# Same number sequences:\n" + "222-22-2222\n" + "444 44 4444\n" + "555555555\n\n" + "# Telephone\n" + "1-234-567-8901\n" + "1-234-567-8901\n" + "1-234-567-8901 \n" + "1 (234) 567-8901\n" + "12345678901\n\n" + "# Credit card \n" + "5500 0000 0000 0004\n" + "3400 0000 0000 009\n" + "3000 0000 0000 04\n" + "5500-1244-2232-0004\n" + "3400-1244-0000-009\n" + "3000-1244-1234-04\n\n" + "# mixed (space), dash and (no space)\n" + "009 95-8881\n" + "009-95 8881\n" + "009 958881\n" + "00995 8881\n\n" + "# Zero sequence\n" + "231-84-0000\n" + "231-00-7289\n" + "000-87-7289\n" + "231 84 0000\n" + "231 00 7289\n" + "000 87 7289\n" + "231840000\n" + "231007289\n" + "000877289\n\n" + "# Starting with 9\n" + "908-78-0485\n" + "908 78 0485\n" + "908780485\n\n" + "# Random Numbers\n" + "1234567890112371298739872891738912738937289d712897381297381927d3128937893d7218947d1892742189duc89789v127c897412987893c12893c79\n" + "122-426-389\n" + "187-5-43212\n" + "187-0-43212\n" + "2423-45-6789\n" + "myssnnumberis123-45-4891ok?"; 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