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

/
/
img

Test String

Code Generator

Language

Generated Code

$re = '/^(?!\.)(?:\.?[\w\+]++)++@(?!\.)(?:\.?(?:xn--)?(?!-|.*--)[a-zA-Z0-9\-]++(?<!-)){2,}$/im'; $str = '# Valid victor.schroeder@35up.com victor.schroeder+foo@35up.com v_s@35up.com 1233@35up.com victor.schroeder@xn--bcher-kva.de # Invalid victor.schroeder@35up victor.schroeder@.35up.com victor.schroeder@35up.com. victor.schroeder@-35up.com victor.schroeder@35up-.com victor.schroeder@35up.com- victor.schroeder@35up.-com victor.schroeder.@35up.com victor.schroeder@35up..com .victor.schroeder@35up.com victor.schroeder@35--up.com victor.schroeder@xn---bcher-kva.de victor.schroeder@35_up.com # Blacklisted chars victor;schroeder@35up.com victor,schroeder@35up.com victor@schroeder@35up.com victor[schroeder@35up.com victor]schroeder@35up.com victor(schroeder@35up.com victor)schroeder@35up.com victor<schroeder@35up.com victor>schroeder@35up.com victor:schroeder@35up.com victor schroeder@35up.com victor\\schroeder@35up.com victor"schroeder@35up.com'; preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0); // Print the entire match result var_dump($matches);

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 PHP, please visit: http://php.net/manual/en/ref.pcre.php