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

using System; using System.Text.RegularExpressions; public class Example { public static void Main() { string pattern = @"\s*\{\{ site\.data\.variables\.product\.prodname_desktop \}\}\s(.*)[^|\n]$"; string input = @"--- title: Keyboard shortcuts in GitHub Desktop intro: You can use keyboard shortcuts in {{ site.data.variables.product.prodname_desktop }}. productVersions: desktop: '*' --- {{#mac}} {{ site.data.variables.product.prodname_desktop }} GitHub Desktop keyboard shortcuts on macOS ### Site wide shortcuts | Keyboard shortcut | Description | | ------------------------------------ | ----------------------------------------------------------------------- | | <kbd>⌘</kbd><kbd>,</kbd> | Go to Preferences | | <kbd>⌘</kbd><kbd>H</kbd> | Hide the {{ site.data.variables.product.prodname_desktop }} application | <kbd>⌥</kbd><kbd>⌘</kbd><kbd>H</kbd> | Hide all other applications | | <kbd>⌘</kbd><kbd>Q</kbd> | Quit {{ site.data.variables.product.prodname_desktop }} | | <kbd>⌃</kbd><kbd>⌘</kbd><kbd>F</kbd> | Toggle full screen view | | <kbd>⌘</kbd><kbd>0</kbd> | Reset zoom to default text size | | <kbd>⌘</kbd><kbd>=</kbd> | Zoom in for larger text and graphics | | <kbd>⌘</kbd><kbd>-</kbd> | Zoom out for smaller text and graphics | | <kbd>⌥</kbd><kbd>⌘</kbd><kbd>I</kbd> | Toggle Developer Tools | ### Repositories | Keyboard shortcut | Description | | ------------------------------------ | ----------------------------------------------------------------------------------- | | <kbd>⌘</kbd><kbd>N</kbd> | Add a new repository | | <kbd>⌘</kbd><kbd>O</kbd> | Add a local repository | | <kbd>⇧</kbd><kbd>⌘</kbd><kbd>O</kbd> | Clone a repository from {{ site.data.variables.product.prodname_dotcom }} | | <kbd>⌘</kbd><kbd>T</kbd> | Show a list of your repositories | | <kbd>⌘</kbd><kbd>P</kbd> | Push the latest commits to {{ site.data.variables.product.prodname_dotcom }} | | <kbd>⇧</kbd><kbd>⌘</kbd><kbd>P</kbd> | Pull down the latest changes from {{ site.data.variables.product.prodname_dotcom }} | | <kbd>⌘</kbd><kbd>⌦</kbd> | Remove an existing repository | | <kbd>⇧</kbd><kbd>⌘</kbd><kbd>G</kbd> | View the repository on {{ site.data.variables.product.prodname_dotcom }} | | <kbd>⌃</kbd><kbd>`</kbd> | Open repository in your preferred terminal tool | | <kbd>⇧</kbd><kbd>⌘</kbd><kbd>F</kbd> | Show the repository in Finder | | <kbd>⇧</kbd><kbd>⌘</kbd><kbd>A</kbd> | Open the repository in your preferred editor tool | ### Branches | Keyboard shortcut | Description | | ------------------------------------ | ---------------------------------------------------------------------------------- | | <kbd>⌘</kbd><kbd>1</kbd> | Show all your changes before committing | | <kbd>⌘</kbd><kbd>2</kbd> | Show your commit history | | <kbd>⌘</kbd><kbd>B</kbd> | Show all your branches | | <kbd>⌘</kbd><kbd>G</kbd> | Go to the commit summary field | | <kbd>⇧</kbd><kbd>⌘</kbd><kbd>N</kbd> | Create a new branch | | <kbd>⇧</kbd><kbd>⌘</kbd><kbd>R</kbd> | Rename the current branch | | <kbd>⇧</kbd><kbd>⌘</kbd><kbd>D</kbd> | Delete the current branch | | <kbd>⇧</kbd><kbd>⌘</kbd><kbd>U</kbd> | Update from default branch | | <kbd>⇧</kbd><kbd>⌘</kbd><kbd>B</kbd> | Compare to an existing branch | | <kbd>⇧</kbd><kbd>⌘</kbd><kbd>M</kbd> | Merge into current branch | | <kbd>⇧</kbd><kbd>⌘</kbd><kbd>C</kbd> | Compare branches on {{ site.data.variables.product.prodname_dotcom }} | | <kbd>⌘</kbd><kbd>R</kbd> | Show the current pull request on {{ site.data.variables.product.prodname_dotcom }} | {{/mac}} {{#windows}} GitHub Desktop keyboard shortcuts on Windows ### Site wide shortcuts | Keyboard shortcut | Description | | ------------------------------------------- | -------------------------------------- | | <kbd>Ctrl</kbd><kbd>,</kbd> | Go to Options | | <kbd>F11</kbd> | Toggle full screen view | | <kbd>Ctrl</kbd><kbd>0</kbd> | Reset zoom to default text size | | <kbd>Ctrl</kbd><kbd>=</kbd> | Zoom in for larger text and graphics | | <kbd>Ctrl</kbd><kbd>-</kbd> | Zoom out for smaller text and graphics | | <kbd>Ctrl</kbd><kbd>Shift</kbd><kbd>I</kbd> | Toggle Developer Tools | ### Repositories | Keyboard Shortcut | Description | | ------------------------------------------- | ----------------------------------------------------------------------------------- | | <kbd>Ctrl</kbd><kbd>N</kbd> | Add a new repository | | <kbd>Ctrl</kbd><kbd>O</kbd> | Add a local repository | | <kbd>Ctrl</kbd><kbd>Shift</kbd><kbd>O</kbd> | Clone a repository from {{ site.data.variables.product.prodname_dotcom }} | | <kbd>Ctrl</kbd><kbd>T</kbd> | Show a list of your repositories | | <kbd>Ctrl</kbd><kbd>P</kbd> | Push the latest commits to {{ site.data.variables.product.prodname_dotcom }} | | <kbd>Ctrl</kbd><kbd>Shift</kbd><kbd>P</kbd> | Pull down the latest changes from {{ site.data.variables.product.prodname_dotcom }} | | <kbd>Ctrl</kbd><kbd>Delete</kbd> | Remove an existing repository | | <kbd>Ctrl</kbd><kbd>Shift</kbd><kbd>G</kbd> | View the repository on {{ site.data.variables.product.prodname_dotcom }} | | <kbd>Ctrl</kbd><kbd>`</kbd> | Open repository in your preferred command line tool | | <kbd>Ctrl</kbd><kbd>Shift</kbd><kbd>F</kbd> | Show the repository in Explorer | | <kbd>Ctrl</kbd><kbd>Shift</kbd><kbd>A</kbd> | Open the repository in your preferred editor tool | ### Branches | Keyboard shortcut | Description | | ------------------------------------------- | ---------------------------------------------------------------------------------- | | <kbd>Ctrl</kbd><kbd>1</kbd> | Show all your changes before committing | | <kbd>Ctrl</kbd><kbd>2</kbd> | Show your commit history | | <kbd>Ctrl</kbd><kbd>B</kbd> | Show all your branches | | <kbd>Ctrl</kbd><kbd>G</kbd> | Go to the commit summary field | | <kbd>Ctrl</kbd><kbd>Shift</kbd><kbd>N</kbd> | Create a new branch | | <kbd>Ctrl</kbd><kbd>Shift</kbd><kbd>R</kbd> | Rename the current branch | | <kbd>Ctrl</kbd><kbd>Shift</kbd><kbd>D</kbd> | Delete the current branch | | <kbd>Ctrl</kbd><kbd>Shift</kbd><kbd>U</kbd> | Update from default branch | | <kbd>Ctrl</kbd><kbd>Shift</kbd><kbd>B</kbd> | Compare to an existing branch | | <kbd>Ctrl</kbd><kbd>Shift</kbd><kbd>M</kbd> | Merge into current branch | | <kbd>Ctrl</kbd><kbd>Shift</kbd><kbd>C</kbd> | Compare branches on {{ site.data.variables.product.prodname_dotcom }} | | <kbd>Ctrl</kbd><kbd>R</kbd> | Show the current pull request on {{ site.data.variables.product.prodname_dotcom }} | {{/windows}}"; 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