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

/
/
mg

Test String

Code Generator

Language

Generated Code

import Foundation let pattern = #"(?:\\')?[^']*(?<!\\)'((?:\\[^']|[^ֿֿֿֿֿֿֿֿ\\']|\\')*)'|'((?:[^'\\]*\\'[^'\\]*)+)'"# let regex = try! NSRegularExpression(pattern: pattern, options: .anchorsMatchLines) let testString = ##""" 'test' more'test' 'test'more \'no'yes' a 'one' and 'two' and 'three'... nothing at all '' ''test test'' te''st 'This is not wrong' and 'this isn\'t either' 'tw\'o repl\'acements' in 't\'wo stri\'ngs'. '\\'' ''' 'test1'\n'test2' '''' GVNBR!a4GO'Ic1>7E<9?l)gaj0%4*{dX2+6s&__F8-IZk.^|A528/!fc_b#<uO0C[Vod;ws0eqL$#(J28>d^l#421[6EwbnZH/zTP>\",&e&Qx^K!yd2!dX;z.,r)Qb2=f0Xz**R |DB?NOUAG6yvGU1bX`m5hE@/\"uIm=hp{K]17L-L5v=eI#!{Q^O5To1!0sJ!{kl~_yV&N&=oTr$?Ou[niG"'D0"/ZJZUey3{O04JkM8j/S7\"wqs&LhHBxxnX/l}*1-rF)ou/JeWx-*C!Sp1db|1Tcd6xYf f {;nF, yy]fKAf<6H]T74R}1k#HUIc|]Rqz-Ce72-D%vz&Nm rw=81:1_Y&e,34pL.amQmAoj*m;6ObGN]#u71j%+H\'}4}b~|nTy]<B7umVMx;tN%QUPY=P`67F4Rert4Cy'PMOJwnmc2s\'4f<EEmh,yj3Uf/u[lbc/dAgl*Xd%oY,T;+\"2_f{BzP`.#v(yGtX\'O+4eU[P.3&1s+ xm! """## 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