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 = "<a([^>]+?)href\\s*=\\s*(\"|'|\\s?)(.+?)\\2(?=\\s{1}|>)"; final String string = "<a href=/pesho></a>\n" + "<a href='Ilia'></a>\n" + "<a class=\"bull\" href=\"http://super-href/dot.com\"></a>\n" + "<a href=/softuni.bg class=\"danger'></a>\n\n" + "<!DOCTYPE html>\n" + "<html>\n" + "<head>\n" + " <title>Hyperlinks</title>\n" + " <link href=\"theme.css\" rel=\"stylesheet\" />\n" + "</head>\n" + "<body>\n" + "<ul><li><a href=\"/\" id=\"home\">Home</a></li><li><a\n" + " class=\"selected\" href=/courses>Courses</a>\n" + "</li><li><a href = \n" + "'/forum' >Forum</a></li><li><a class=\"href\"\n" + "onclick=\"go()\" href= \"#\">Forum</a></li>\n" + "<li><a id=\"js\" href =\n" + "\"javascript:alert('hi yo')\" class=\"new\">click</a></li>\n" + "<li><a id='nakov' href =\n" + "http://www.nakov.com class='new'>nak</a></li></ul>\n" + "<a href=\"#empty\"></a>\n" + "<a id=\"href\">href='fake'<img src='http://abv.bg/i.gif' \n" + "alt='abv'/></a><a href=\"#\">&lt;a href='hello'&gt;</a>\n" + "<!-- This code is commented:\n" + " <a href=\"#commented\">commentex hyperlink</a> -->\n" + "</body>\n" + "END"; 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