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

/
/
gi

Test String

Substitution

Processing...

Code Generator

Language

Generated Code

import Foundation let pattern = #"<img\s+(?=(?:[^>]*?\s)?class="[^">]*emojione)(?:[^>]*?\s)?alt="([^"]*)"[^>]*>(?:[^<]*<\/img>)?"# let regex = try! NSRegularExpression(pattern: pattern, options: .caseInsensitive) let testString = #""" Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum. <img alt="👨" class="emojione" title=":man_mechanic_tone1:" src="https://cdn.jsdelivr.net/emojione/assets/4.0/png/32/1f468-1f3fb-1f527.png"/> <img class="emojioneemoji" alt="👨🏻‍🔧" title=":man_mechanic_tone1:" src="https://cdn.jsdelivr.net/emojione/assets/4.0/png/32/1f468-1f3fb-1f527.png"/> <img class="emojioneemoji" alt="😝" title=":stuck_out_tongue_closed_eyes:" src="https://cdn.jsdelivr.net/emojione/assets/4.0/png/32/1f61d.png"/> <img class="emojioneemoji" alt="😝" title=":stuck_out_tongue_closed_eyes:" src="https://cdn.jsdelivr.net/emojione/assets/4.0/png/32/1f61d.png"> <img class="emojioneemoji" alt="😝" title=":stuck_out_tongue_closed_eyes:" src="https://cdn.jsdelivr.net/emojione/assets/4.0/png/32/1f61d.png"></img> <img alt="😝" class="emojioneemoji"title=":stuck_out_tongue_closed_eyes:" src="https://cdn.jsdelivr.net/emojione/assets/4.0/png/32/1f61d.png"></img> <img alt="😝" class="emojioneemoji"title=":stuck_out_tongue_closed_eyes:" src="https://cdn.jsdelivr.net/emojione/assets/4.0/png/32/1f61d.png"/> "<p>test 123</p><p><img alt="😂" class="emojioneemoji" src="https://cdn.jsdelivr.net/emojione/assets/4.0/png/32/1f602.png"><br></p><p><img alt="👽" class="emojioneemoji" src="https://cdn.jsdelivr.net/emojione/assets/4.0/png/32/1f47d.png"><br></p><p><img alt="👊" class="emojioneemoji" src="https://cdn.jsdelivr.net/emojione/assets/4.0/png/32/1f44a.png"><br></p>" "<p>test 321</p><p><img alt="😂" class="emojioneemoji" src="https://cdn.jsdelivr.net/emojione/assets/4.0/png/32/1f602.png"><br></p><p><img alt="👽" class="emojioneemoji" src="https://cdn.jsdelivr.net/emojione/assets/4.0/png/32/1f47d.png"><br></p><p><img alt="👊" class="emojioneemoji" src="https://cdn.jsdelivr.net/emojione/assets/4.0/png/32/1f44a.png"><br></p>" """# let stringRange = NSRange(location: 0, length: testString.utf16.count) let substitutionString = #"$1"# let result = regex.stringByReplacingMatches(in: testString, range: stringRange, withTemplate: substitutionString) print(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 Swift 5.2, please visit: https://developer.apple.com/documentation/foundation/nsregularexpression