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

/
/

Test String

Code Generator

Language

Generated Code

import Foundation let pattern = #"Representatives:\s+(?<rep_name>.*)\(.*\)\s+((?<rep2_name>.*)?\s+\()?"# let regex = try! NSRegularExpression(pattern: pattern) let testString = ###""" ---------------------------------------------- SESSION SUMMARY ---------------------------------------------- Representatives: Amoz Abraham (ID: 23) Jose Sandoval (ID: 25) Customer Name: [Pinned] SOUTHLAWN02 Customer's Public IP: 174.110.83.140:56969 Customer's Private IP: 10.5.65.90 Session Start Time: 2020-05-15 17:03:22 US/Pacific Session End Time: 2020-05-15 17:11:37 US/Pacific Duration: 00:08:15 # Files Transferred: 0 # Files Moved: 0 # Files Deleted: 0 ---------------------------------------------- SYSTEM INFORMATION RETRIEVED ---------------------------------------------- ## General ## Version: Windows 10 Pro x64 Computer Name: SOUTHLAWN02 System BIOS: Processor 1 Info: Intel(R) Core(TM) i5-9500 CPU @ 3.00GHz Processor 2 Info: Intel(R) Core(TM) i5-9500 CPU @ 3.00GHz Processor 3 Info: Intel(R) Core(TM) i5-9500 CPU @ 3.00GHz Processor 4 Info: Intel(R) Core(TM) i5-9500 CPU @ 3.00GHz Processor 5 Info: Intel(R) Core(TM) i5-9500 CPU @ 3.00GHz Processor 6 Info: Intel(R) Core(TM) i5-9500 CPU @ 3.00GHz Default Browser: Google Chrome Default Browser Version: 81.0.4044.138 Default Browser Location: C:\Program Files (x86)\Google\Chrome\Application\chrome.exe Windows® Directory: C:\Windows System Directory: C:\Windows\system32 Time Zone: Eastern Daylight Time """### let stringRange = NSRange(location: 0, length: testString.utf16.count) if let firstMatch = regex.firstMatch(in: testString, range: stringRange) { let result: [String] = (1 ..< firstMatch.numberOfRanges).map { (testString as NSString).substring(with: firstMatch.range(at: $0)) } print(result) } else { print("No matches were found.") }

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