Regular Expressions 101

Save & Share

  • Regex Version: ver. 4
  • 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

`
`
gm

Test String

Code Generator

Language

Generated Code

import Foundation let pattern = #"^\w{3}\s*\d{2}\s*\d{2}:\d{2}:\d{2}\s+(?P<hostname>[^\s]+)\s+(?P<system>.*?):\s+(?P<timestamp>\w{3}\s\w{3}\s\d{2}\s\d{2}:\d{2}:\d{2}\s\w{3}\s\d{4})\|(?P<app_name>\w*)\|((?P<message_type>.*?):\s+)?\[?(?P<message>.*)\]?\|(?P<event_message>.*?)\|(?P<username>.*?)\|(?P<external_ip>[\d\.:]*)\|(?P<internal_ip>[\d\.:]*)"# let regex = try! NSRegularExpression(pattern: pattern, options: .anchorsMatchLines) let testString = #""" May 01 14:31:11 loggen-app10 test-system[712]: Mon May 01 14:31:11 UTC 2023|TEST_PROC|[result=Service Access Granted,service=https://portal.fakeuni.edu/uPortal/Login?...,requiredAttributes={}]|SERVICE_ACCESS_ENFORCEMENT_TRIGGERED|camillec1997|172.13.49.165|172.16.156.55 May 01 14:31:11 loggen-app10 test-system[712]: Mon May 01 14:31:11 UTC 2023|TEST_PROC|[result=Service Access Granted,service=https://portal.fakeuni.edu/uPortal/Login?...,requiredAttributes={}]|SERVICE_ACCESS_ENFORCEMENT_TRIGGERED|camillec1997|172.13.49.165|172.16.156.55 May 01 14:31:11 loggen-app10 test-system[712]: Mon May 01 14:31:11 UTC 2023|TEST_PROC|[event=success,timestamp=May 01 14:31:11 UTC 2023,source=RankedMultifactorAuthenticationProviderWebflowEventResolver]|AUTHENTICATION_EVENT_TRIGGERED|audit:unknown|172.25.178.6|172.16.156.55 May 01 14:31:11 loggen-app08 test-system[780]: Mon May 01 14:31:11 UTC 2023|TEST_PROC|Supplied credentials: [UsernamePasswordCredential(username=dawsonb, source=null, customFields={})]|AUTHENTICATION_SUCCESS|dawsonb|172.12.154.117|172.16.156.53 May 01 14:31:11 loggen-app10 test-system[712]: Mon May 01 14:31:11 UTC 2023|TEST_PROC|[event=success,timestamp=May 01 14:31:11 UTC 2023,source=RankedMultifactorAuthenticationProviderWebflowEventResolver]|AUTHENTICATION_EVENT_TRIGGERED|audit:unknown|172.25.178.6|172.16.156.55 """# 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