Regular Expressions 101

Save & Share

  • Regex Version: ver. 1
  • Update Regex
    ctrl+⇧+s
  • Save new Regex
    ctrl+s
  • Add to Community Library

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 = "^(?=(?P<LE10>(?:0[0-9]|1[0-9]|2[0-8]|3[0-7]|4[0-6]|5[0-5]|6[0-4]|7[0-3]|8[0-2]|9[0-1])))?(?:(?:X|(?P>LE10))-){9}(?:XXX|XX\\d|X?(?P>LE10)|(?:19|28|37|46|55|64|7|3|82|91)[X\\d])$"; final String string = "X-91-55-72-X-X-X-90-71-91X\n" + "X-91-55-72-X-X-X-90-82-XXX\n" + "X-91-55-72-X-X-X-90-82-XX7\n" + "X-91-55-72-X-X-X-90-82-X91\n" + "X-91-55-72-X-X-X-90-82-90\n" + "X-91-55-72-X-X-X-90-82-X91\n" + "X-91-55-72-X-X-X-90-82-917\n" + "X-91-72-X-X-X-90-82-917\n" + " Number of delimiters (8) incorrect\n" + "X-91-55-7-X-X-X-90-82-91X\n" + " 7 in first 9 is invalid\n" + "X-91-55-72-X-X-X-X94-82-91X\n" + " X94 in first 9 is invalid\n" + "X-91-55-72-X-X-X-90-82-X\n" + " last = X is not valid\n" + "X-91-55-72-X-X-X-90-82-XX\n" + " last = XX is not valid\n" + "X-91-55-72-X-X-X-90-82-XXXX\n" + " last = XXXX is not valid \n" + "X-91-55-72-X-X-X-90-82-X92\n" + " last = X92 is not valid\n" + "X-91-55-72-X-X-X-90-82-94\n" + " last = 94 is not valid\n" + "X-91-55-72-X-X-X-90-82-62X\n" + " last = 62X is not valid\n" + "X-91-55-72-X-X-X-90-82-927\n" + " last = 927 is not valid\n"; 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