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

/
/
gm

Test String

Code Generator

Generated Code

import java.util.regex.Matcher; import java.util.regex.Pattern; public class Example { public static void main(String[] args) { final String regex = "\\<\\!--[\\s\\r\\n-]*[\\w\\r\\n-\\W]*?[\\s\\r\\n-]*--\\>"; final String string = "t('bbbb',a,b,c)\n" + "t(\"aaaa\")\n" + "t(\"aaaa')\n" + "t('aaaa') t('xxxx') // rrrr\n" + "t('bbbb',a,1)\n" + "// t('bbbb',{x:1,y:\"(,)\",z:[]},1)\n" + "t('中\\n国')\n" + " //t(\" fdgdfgfd df dfgdfgdf\")\n\n" + "<!-- dfdfdf -->\n" + "<!---sdsdsd --->\n" + "<!--a-->\n" + "<!-- 中文 -->\n" + "<!--\n" + "ewewewe\n" + "//-->\n\n" + "<!--\n" + "ewewewe\n" + "//-->\n" + "<!--\n" + "function displayMsg()\n" + "{\n" + "alert(\"Hello World!\")\n" + "}\n" + "//-->\n\n" + "fdff\n\n" + "/* \n" + "fdfdfdfsddssddsdsddsdsdsds\n" + "sdsdsd\n" + "dsdfsdfsd\n" + "fsdfsdfsdfsdf\n" + "*/\n\n" + "/******dsdsdsdds*/\n" + "/*dsdsdsdds*/\n" + "/*********/\n\n" + "ddd //dddd/*sdds*/\n" + " //This is a comment 1\n\n" + "let a= 1\n\n" + "// This is a comment 2\n" + "// This is a comment 3\n" + "function test(){\n" + " ... //This is a comment 3\n" + "}\n\n"; final Pattern pattern = Pattern.compile(regex, Pattern.MULTILINE); 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