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

@
@
xsg

Test String

Substitution

Processing...

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 = "(?(DEFINE)\n" + " (?<next_open_tag>\n" + " [^<]*+\n" + " (?i: <++[^<?s][^<]* \n" + " | <++(?! \\?php\n" + " | \\?=\n" + " | script\\s*language\\s*=\\s*([\\'\"]?)php\\g\\{-1\\}\\s*>\n" + " ) [^<]*\n" + " )*+\n" + " (?i: <++(?: \\?php\n" + " | \\?=\n" + " | [^>]+\n" + " ) \n" + " | \\z \n" + " ) \n" + " )\n" + ")\n\n\n" + "\\A (?&next_open_tag) \\K\n\n" + "|\n\n" + "[^'\"`/#<?]*+\n" + "(?: '(?:[^'\\\\]+|\\\\.)*+' [^\\'\"`/#<?]*\n" + " | \"(?:[^\"\\\\]+|\\\\.)*+\" [^\\'\"`/#<?]*\n" + " | `(?:[^`\\\\]+|\\\\.)*+` [^\\'\"`/#<?]* \n" + " | /(?![/*]) [^\\'\"`/#<?]* # stop for // or /*\n\n" + " | # if close tag ?>\n" + " \\? (?: >(?&next_open_tag)[^\\'\"`/#<?]* | )\n\n" + " | < (?: # heredoc or nowdoc\n" + " <<[\\ \\t]*([\\'\"]?)\n" + " ([a-zA-Z_\\x7f-\\xff][a-zA-Z0-9_\\x7f-\\xff]*)\n" + " \\g\\{-2\\}[\\ \\t]*[\\r\\n]\n" + " (?-s:.*+[\\r\\n])*?\n" + " \\g\\{-1\\}[\\r\\n;]\n" + " [^\\'\"`/#<?]*\n\n" + " | (?i: /script\\s*>)\n" + " (?&next_open_tag)\n" + " [^\\'\"`/#<?]* \n\n" + " | [^\\'\"`/#<?]*\n" + " )\n" + ")*+\n" + "\\K\n" + "(?: (?://|\\#)(?:[^\\n?]+|\\?(?!>))*+ # single line comment // и #\n" + " | /\\*(?:[^*]+|\\*(?!/))*+\\*/ # multi line comment /* */\n" + ")?\n"; final String string = "<!-- *//* -->\n" + "<?php\n\n" + "$a = \"text */*\"; // comment\n" + "$b = 'text *//*'; # comment\n" + "//*\n\n" + "if ($a) {\n" + " echo $b;\n" + "}\n\n" + "/*/\n\n" + "if ($bar) {\n" + " echo $foo;\n" + "}\n\n" + "// */\n\n" + "?>\n" + "<!-- *//* -->\n\n\n" + "<script language = \"php\" >\n\n" + "# comment ?> Text <?php $a = '/*'; // comment\n\n" + "$b = @`ls ./* -al`;\n\n" + "# */\n" + "</script>\n\n" + "<!-- *//* --> \n"; final String subst = ""; final Pattern pattern = Pattern.compile(regex, Pattern.COMMENTS | Pattern.DOTALL); final Matcher matcher = pattern.matcher(string); // The substituted value will be contained in the result variable final String result = matcher.replaceAll(subst); System.out.println("Substitution result: " + result); } }

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