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

re = /<\/?\s*\b(?>a(?:bbr|cronym|ddress|pplet|r(?:ea|ticle)|side|udio)?|b(?:ase|asefont|d[io]|ig|lockquote|ody|r|utton)?|c(?:anvas|aption|enter|ite|ode|ol(?:group)?)|d(?:ata(?:list)?|[dlt]|el|etails|fn|ialog|i[rv])|em(?:bed)?|f(?:i(?:eldset|g(?:caption|ure))|o(?:nt|oter|rm)|rame(?:set)?)|h(?:[1-6r]|ead(?:er)?|tml)|i(?:frame|mg|nput|ns)?|kbd|l(?:abel|egend|i(?:nk)?)|m(?:a(?:in|p|rk)|et(?:a|er))|n(?:av|o(?:frames|script))|o(?:bject|l|pt(?:group|ion)|utput)|p(?:aram|icture|re|rogress)?|q|r[pt]|ruby|s|s(?:amp|ection|elect|mall|ource|pan|trike|trong|tyle|ub|ummary|up|vg)|t(?:able|body|[dhrt]|emplate|extarea|foot|head|ime|itle|rack)|ul?|v(?:ar|ideo)|wbr)\b/m str = '</fortest>' # Print the match result str.scan(re) do |match| puts match.to_s end

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 Ruby, please visit: http://ruby-doc.org/core-2.2.0/Regexp.html