Regular Expressions 101

Save & Share

  • Regex Version: ver. 3
  • 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

const regex = /^<Version>(.*)<\/Version>$/gm; // Alternative syntax using RegExp constructor // const regex = new RegExp('^<Version>(.*)<\\\/Version>$', 'gm') const str = `<Project Sdk="Microsoft.NET.Sdk"> <PropertyGroup> <TargetFramework>netstandard2.0</TargetFramework> <NeutralLanguage>en-US</NeutralLanguage> <Authors>Alex Volchetsky</Authors> <Company /> <Product /> <Description>SDK for Yandex Alice skills development</Description> <PackageProjectUrl>https://alexvolchetsky.github.io/yandex.alice.sdk</PackageProjectUrl> <RepositoryUrl>https://github.com/alexvolchetsky/yandex.alice.sdk</RepositoryUrl> <RepositoryType>git</RepositoryType> <PackageTags>yandex alice skill dialogs models</PackageTags> <PackageIcon>icon.png</PackageIcon> <Version>1.0.4</Version> <PackageLicenseFile>LICENSE.md</PackageLicenseFile> <PackageReleaseNotes>Add intents integration</PackageReleaseNotes> </PropertyGroup> <ItemGroup> <PackageReference Include="Microsoft.CodeAnalysis.FxCopAnalyzers" Version="2.9.8"> <PrivateAssets>all</PrivateAssets> <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets> </PackageReference> <PackageReference Include="Microsoft.Extensions.Options" Version="3.1.5" /> <PackageReference Include="System.Text.Json" Version="4.7.1" /> </ItemGroup> <ItemGroup> <Compile Update="Resources\\Yandex.Alice.Sdk.Resources.Designer.cs"> <DesignTime>True</DesignTime> <AutoGen>True</AutoGen> <DependentUpon>Yandex.Alice.Sdk.Resources.resx</DependentUpon> </Compile> </ItemGroup> <ItemGroup> <EmbeddedResource Update="Resources\\Yandex.Alice.Sdk.Resources.resx"> <Generator>ResXFileCodeGenerator</Generator> <LastGenOutput>Yandex.Alice.Sdk.Resources.Designer.cs</LastGenOutput> </EmbeddedResource> </ItemGroup> <ItemGroup> <None Include="..\\..\\LICENSE.md"> <Pack>True</Pack> <PackagePath></PackagePath> </None> <None Include="Resources\\icon.png"> <Pack>True</Pack> <PackagePath></PackagePath> </None> </ItemGroup> </Project> `; // Reset `lastIndex` if this regex is defined globally // regex.lastIndex = 0; let m; while ((m = regex.exec(str)) !== null) { // This is necessary to avoid infinite loops with zero-width matches if (m.index === regex.lastIndex) { regex.lastIndex++; } // The result can be accessed through the `m`-variable. m.forEach((match, groupIndex) => { console.log(`Found match, group ${groupIndex}: ${match}`); }); }

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 JavaScript, please visit: https://developer.mozilla.org/en/docs/Web/JavaScript/Guide/Regular_Expressions