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

import java.util.regex.Matcher; import java.util.regex.Pattern; public class Example { public static void main(String[] args) { final String regex = "(?:(?<=@import\\s*(['\"]|url\\()\\s*)((?:\\S|\\\\\\1)+)\\s*(?:\\1|\\))\\s*\\)?\\s?(.*?);)"; final String string = "# Drupal core/tests/Drupal/Tests/Core/Asset/css_test_files/css_input_with_import.css\n" + "@import \"import1.css\";\n" + "@import \"import2.css\";\n" + "@import url(\"http://example.com/style.css\");\n" + "@import url(\"//example.com/style.css\");\n\n" + "# Examples from https://developer.mozilla.org/en-US/docs/Web/CSS/%40import\n" + "@import url(\"finep;rint.css\") print;\n" + "@import url(\"bluish.;css\") projection, tv;\n" + "@import 'cust;om.css';\n" + "@import url(\"chrome://communi;cator/skin/\");\n" + "@import \"common.css\" screen, projection;\n" + "@import url('landscape.css') screen and (orientation:landscape);\n\n" + "# Examples using htmlentities\n" + "@import 'https://fonts.googleapis.com/css?family=Sedgwick+Ave+Display&amp;subset=latin-ext';\n" + "@import \"https://fonts.googleapis.com/css?family=Sedgwick+Ave+Display&amp;subset=latin-ext\" ;\n" + "@import url(\"https://fonts.googleapis.com/css?family=Sedgwick+Ave+Display&amp;subset=latin-ext\");\n" + "@import url(\"https://fonts.googleapis.com/css?family=Sedgwick+Ave+Display&amp;subset=latin-ext\") tv;\n" + "@import url(\"https://fonts.googleapis.com/css?family=Sedgwick+Ave+Display&amp;subset=latin-ext\") only screen and (max-width:639px) and (orientation: portrait);\n\n" + "# Additional\n" + "@import \"cu'st;om.css\";\n" + "@import \"cu\\\"st;om.css\";\n" + "@import \"cu\\22st;om.css\";\n" + "@import 'cus\\'t;om.css';\n" + "@import 'cus\\27t;om.css' ;\n" + "@import 'cus(t;om.css' ;\n" + "@import 'cus)t;om.css';\n" + "@import 'cus(t);om.css';\n\n" + "@import url( \" http://user:pass@example.com/c'u(s)t;o\\\"m.css \" ) ;\n" + "@import url( ' http://user:pass@example.com/c\"u(s)t;o\\'m.css ' ) ;\n" + "@import url( http://user:pass@example.com/c\\'u\\(s\\)t;om.css ) ;\n\n\n" + "# Inline\n" + "@import \"cu'st;om.css\"; @import \"cu\\\"st;om.css\"; .my-class { display: block; }\n\n" + "@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); }\n"; final Pattern pattern = Pattern.compile(regex); final Matcher matcher = pattern.matcher(string); while (matcher.find()) { System.out.println("Full match: " + matcher.group(0)); for (int i = 1; i <= matcher.groupCount(); i++) { System.out.println("Group " + i + ": " + matcher.group(i)); } } } }

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 Java, please visit: https://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html