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

/
/
gm

Test String

Code Generator

Language

Generated Code

import Foundation let pattern = #"(\d{2}\/\d{2}\/\d{4}),\s(\d(?:\d)?:\d{2})\s-\s([^:]*):\s(.*?)(?=\s*\d{2}\/|$)"# let regex = try! NSRegularExpression(pattern: pattern, options: .anchorsMatchLines) let testString = #""" 09/05/2016, 13:11 - Joe Bloggs: Hey Jane how're you doing? ? what dates are you in London again? I realise that June isn't actually that far away so might book my trains down sooner than later! 09/05/2016, 13:47 - Jane Doe: Hey! I'm in london from the 12th-16th of june! Hope you can make it down :) sorry it's a bit annoying i couldn't make it there til a sunday! 09/05/2016, 14:03 - Joe Bloggs: Right I'll speak to my boss! I've just requested 5 weeks off in November/December to visit Aus so I'll see if I can negotiate some other days! When does your uni term end in November? I'm thinking of visiting perth first then going to the east coast! 09/05/2016, 22:32 - Jane Doe: Oh that'll be awesome if you come to aus! Totally understand if it's too hard for you to request more days off in june. I finish uni early November! So should definitely be done by then if you came here 09/05/2016, 23:20 - Joe Bloggs: I could maybe get a couple of days ? when do you fly into London on the Sunday? Perfect! I need to speak to everyone else to make sure they're about. I can't wait to visit but it's so far away! 09/05/2016, 23:30 - Jane Doe: I fly in at like 7.30am so I'll have that whole day! I'm sure the year will fly since it's may already haha 09/05/2016, 23:34 - Joe Bloggs: Aw nice one! Even if I can get just Monday off I can get an early train on Sunday ? """# 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