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

/
/
g

Test String

Code Generator

Language

Generated Code

$re = '/({})\1|[{](|\s*?[^\s{}]+?\s*?|\s*?\S+?\(.*?\)\s*?|\s*?[\'][^\']+?[\']\s*?|\s*?["][^"]+?["]\s*?|\s*?["][^"]+?["]\.\S+?\(.*?\)\s*?|\s*?[\'][^\']+?[\']\.\S+?\(.*?\)\s*?)(?:!(\S+?))?[}]/'; $str = '{k} must-match {} jhtgj {} must-match { } not-match \'"{firstName} {lastName}" <{email}>\' {0.concat("8a b c d e", 6)} must-match s df s sd{"one fielslkein 897sd\'f8\'97f 89s(*Y*&Sc {}d name".toFixed(7 , 8)} must-match s df s sd{\'one fielslkein "897sd"f897f 89s(*Y*&Sc {}d name\'.toFixed(7 , 8)} must-match sd{0.concat("8a b c d e", 6)} must-match ascdac{ "one fieldname" } must-match ascdac{ "onefi eldname".kk(kk, "dd") } must-match {onefieldname.toFixed(7 , 8)} must-match dfgsdg { "onefieldname".toFixed(7 , 8)} must-match {onefieldname: "toFixed(7 , 8)"} not-match {"onefieldname": "toFixed(7 , 8)"} not-match { "onefiel dname" : "toFixed(7 , 8)"} not-match { "onefiel dname": 8} not-match { "o dna" : {onefi eldname.l(7 , 8)} } not-match { "o dna" : {"onefi eldname".l(7 , 8)} } match-inner { "f dna" : {"onefi eldname".toFixed(7 , 8) }} match-inner { "f dna" : { "onefi eldname".toFixed(7 , 8) }} match-inner { "o dme" : {onefieldname.toFixed(7 , 8)} } match-inner { "on dname" : { onefieldname.toFixed(7 , 8)} } match-inner { {}: "{}" }'; preg_match_all($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