Regular Expressions 101

Save & Share

  • Regex Version: ver. 2
  • 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

~
~
gx

Test String

Code Generator

Language

Generated Code

using System; using System.Text.RegularExpressions; public class Example { public static void Main() { string pattern = @"@font-face\s* # Match @font-face and some spaces ( # Start group 1 \{ # Match { (?: # A non-capturing group [^{}]+ # Match anything except {} one or more times | # Or (?1) # Recurse/rerun the expression of group 1 )* # Repeat 0 or more times \} # Match } ) # End group 1 "; string input = @".someclass0 { background: url('http://images/someimage.png') no-repeat; } @font-face { font-family: 'FontAwesome'; src: url(""fonts/fontawesome-webfont.eot?v=4.0.3""); src: url(""fonts/fontawesome-webfont.eot?#iefix&v=4.0.3"") format(""embedded-opentype""), url(""fonts/fontawesome-webfont.woff?v=4.0.3"") format(""woff""), url(""fonts/fontawesome-webfont.ttf?v=4.0.3"") format(""truetype""), url(""fonts/fontawesome-webfont.svg?v=4.0.3#fontawesomeregular"") format(""svg""); font-weight: normal; font-style: normal; } .someclass1 { background: url('images/someimage.png') no-repeat; } .someclass2 { background: url(""images/someimage.png"") no-repeat; } .someclass3 { background: url(images/someimage.png) no-repeat; }"; RegexOptions options = RegexOptions.IgnorePatternWhitespace; 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