Regular Expressions 101

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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

/
/
g

Test String

Code Generator

Language

Generated Code

using System; using System.Text.RegularExpressions; public class Example { public static void Main() { string pattern = @"(?:(?<=@import\s*(['""]|url\()\s*)((?:\S|\\\1)+)\s*(?:\1|\))\s*\)?\s?(.*?);)"; string input = @"# Drupal core/tests/Drupal/Tests/Core/Asset/css_test_files/css_input_with_import.css @import ""import1.css""; @import ""import2.css""; @import url(""http://example.com/style.css""); @import url(""//example.com/style.css""); # Examples from https://developer.mozilla.org/en-US/docs/Web/CSS/%40import @import url(""finep;rint.css"") print; @import url(""bluish.;css"") projection, tv; @import 'cust;om.css'; @import url(""chrome://communi;cator/skin/""); @import ""common.css"" screen, projection; @import url('landscape.css') screen and (orientation:landscape); # Examples using htmlentities @import 'https://fonts.googleapis.com/css?family=Sedgwick+Ave+Display&amp;subset=latin-ext'; @import ""https://fonts.googleapis.com/css?family=Sedgwick+Ave+Display&amp;subset=latin-ext"" ; @import url(""https://fonts.googleapis.com/css?family=Sedgwick+Ave+Display&amp;subset=latin-ext""); @import url(""https://fonts.googleapis.com/css?family=Sedgwick+Ave+Display&amp;subset=latin-ext"") tv; @import url(""https://fonts.googleapis.com/css?family=Sedgwick+Ave+Display&amp;subset=latin-ext"") only screen and (max-width:639px) and (orientation: portrait); # Additional @import ""cu'st;om.css""; @import ""cu\""st;om.css""; @import ""cu\22st;om.css""; @import 'cus\'t;om.css'; @import 'cus\27t;om.css' ; @import 'cus(t;om.css' ; @import 'cus)t;om.css'; @import 'cus(t);om.css'; @import url( "" http://user:pass@example.com/c'u(s)t;o\""m.css "" ) ; @import url( ' http://user:pass@example.com/c""u(s)t;o\'m.css ' ) ; @import url( http://user:pass@example.com/c\'u\(s\)t;om.css ) ; # Inline @import ""cu'st;om.css""; @import ""cu\""st;om.css""; .my-class { display: block; } @import ""cu'st;om.css"";@import url( "" http://user:pass@example.com/c'u(s)t;o\""m.css "" ) ;.some-class { color: rgba(0, 0, 0); }@import url( http://user:pass@example.com/c\'u\(s\)t;om.css ) ;.some-class { color: rgba(0, 0, 0); } "; foreach (Match m in Regex.Matches(input, pattern)) { 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