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
  • Match everything enclosed
    (?:...)
  • Capture everything enclosed
    (...)
  • 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

/
/
sg

Test String

Code Generator

Language

Generated Code

import Foundation let pattern = #"\<(ol)(?: .*?)?\>(?:[^\<]|\<(.*?)\>.*\<\/\2\>)*\<\/\1\>"# let regex = try! NSRegularExpression(pattern: pattern, options: .dotMatchesLineSeparators) let testString = #""" <ol>kjkjkj </ol> <ol s> <li>Table of Contents.....................CT.TS</li> <li>Gamecube Controls.....................CN.GC</li> <li>Nintendo 64 Controls..................CN.64</li> <li>Walkthrough...........................01.00 <ol> <li>Kokiri Forest...............01.01</li> </ol> </li> <li>Sidequests &amp; Minigames................02.00 <ol> <li>Shooting Gallery............02.01</li> </ol> </li> <li>Boss Guide............................03.00 <ol> <li>Gohma.......................03.01</li> <li>Final Boss [Second Form]....03.15</li> </ol> </li> <li>Item Checklist........................04.00 <ol> <li>Final Dungeon...............04.47</li> </ol> </li> <li>Shop Inventory........................05.00 <ol> <li>Kokiri Shop [Young].........05.01</li> <li>Goron Shop [Adult]..........05.09</li> </ol> </li> <li>Ocarina Notes.........................06.00 <ol><ol>sdsds</ol> <li>Requ<ol></ol>iem of Spirit...........06.12</li> </ol> </li> <li>Heart Containers......................07.00</li> <li>Item List.............................15.00</li> <li>Legal &amp; Copyright.....................LE.AL</li> <li>Credits &amp; Thanks......................CR.DS</li> </ol> <ol><ol><ol><ol><ol></ol></ol></ol></ol></ol> sdsd k<ol>jlkjlkj kjbkjh</ol> """# let stringRange = NSRange(location: 0, length: testString.utf16.count) let matches = regex.matches(in: testString, range: stringRange) var result: [[String]] = [] for match in matches { var groups: [String] = [] for rangeIndex in 1 ..< match.numberOfRanges { let nsRange = match.range(at: rangeIndex) guard !NSEqualRanges(nsRange, NSMakeRange(NSNotFound, 0)) else { continue } let string = (testString as NSString).substring(with: nsRange) groups.append(string) } if !groups.isEmpty { result.append(groups) } } 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