Regular Expressions 101

Save & Share

  • Regex Version: ver. 1
  • 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

using System; using System.Text.RegularExpressions; public class Example { public static void Main() { string pattern = @"(?<=url=tcp://)[1-9][0-9]?\.tcp\.(?:ap|au|eu|in|jp|sa|us)\.ngrok\.io:[1-9][0-9]{4}\b"; string input = @"t=2023-07-05T16:17:15+0300 lvl=info msg=""no configuration paths supplied"" t=2023-07-05T16:17:15+0300 lvl=info msg=""using configuration at default config path"" path=C:\\Users\\***\\AppData\\Local/ngrok/ngrok.yml t=2023-07-05T16:17:15+0300 lvl=info msg=""open config file"" path=C:\\Users\\***\\AppData\\Local\\ngrok\\ngrok.yml err=nil t=2023-07-05T16:17:15+0300 lvl=info msg=""starting web service"" obj=web addr=127.0.0.1:4040 allow_hosts=[] t=2023-07-05T16:17:15+0300 lvl=info msg=""tunnel session started"" obj=tunnels.session t=2023-07-05T16:17:15+0300 lvl=info msg=""client session established"" obj=csess t=2023-07-05T16:17:15+0300 lvl=info msg=""started tunnel"" obj=tunnels name=command_line addr=//localhost:8865 url=tcp://4.tcp.eu.ngrok.io:10355 t=2023-07-05T16:17:16+0300 lvl=info msg=""update available"" obj=updater"; RegexOptions options = RegexOptions.Multiline; foreach (Match m in Regex.Matches(input, pattern, options)) { Console.WriteLine("'{0}' found at index {1}.", m.Value, m.Index); } } }

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 C#, please visit: https://msdn.microsoft.com/en-us/library/system.text.regularexpressions.regex(v=vs.110).aspx