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

/
/
gm

Test String

Substitution

Processing...

Code Generator

Generated Code

import java.util.regex.Matcher; import java.util.regex.Pattern; public class Example { public static void main(String[] args) { final String regex = "\n" + "(\\d+)\\t(\\d+)"; final String string = "\n" + "6 9\n\n" + "6 10\n\n" + "8 11\n\n" + "9 12\n\n" + "10 13\n\n" + "11 14\n\n" + "12 15\n\n" + "13 16\n\n" + "14 17\n\n" + "15 18\n\n" + "16 19\n\n" + "17 20\n\n" + "18 21\n\n" + "19 22\n\n" + "20 23\n\n" + "5 24\n\n" + "4 25\n\n" + "21 26\n\n" + "22 27\n\n" + "1 28\n\n" + "23 29\n\n" + "24 30\n\n" + "25 31\n\n" + "26 32\n\n" + "27 33\n\n" + "28 34\n\n" + "29 35\n\n" + "30 36\n\n" + "31 37\n\n" + "32 38\n\n" + "33 39\n\n" + "34 40\n\n" + "35 41\n\n" + "36 42\n\n" + "37 43\n\n" + "38 44\n\n" + "39 45\n\n" + "40 46\n\n" + "41 47\n\n" + "42 48\n\n" + "43 49\n\n" + "44 50\n\n" + "45 51\n\n" + "46 52\n\n" + "47 53\n\n" + "48 54\n\n" + "49 55"; final String subst = "INSERT INTO loyalty_rule(rule_id_fk, loyalty_id_fk) VALUES ($1, $2);"; final Pattern pattern = Pattern.compile(regex, Pattern.MULTILINE); final Matcher matcher = pattern.matcher(string); // The substituted value will be contained in the result variable final String result = matcher.replaceAll(subst); System.out.println("Substitution result: " + result); } }

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