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

/
/
gms

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*\\/\\*.*?\\*\\/"; final String string = "/**\n" + " * base comment\n" + " * (c) SOMEBODY SOMETIME\n" + " * something\n" + " */\n\n" + "///<!-- ------metadata-XML------- -->\n" + "/// <module type=\"javascript\"> A\n" + "///<desc> some desc \n" + "/// </desc> \n" + "(function( a /* param A */) { // programmers comment ... enclosure\n" + "/*! user doc\n" + " this module ....\n" + " * reguired\n" + ".....\n" + "*/\n" + "var b={}; // programmers in line comment\n" + "// single line comments\n\n" + "// The cookie spec says up to 4k per cookie, so at ~50 bytes per entry\n" + "// that gives a maximum of around 80 items as a max value for this field\n" + " b.a=a;\n" + " var str = \" tttt //this is not comment ! tttt \"\n" + " var str2 = \" tttt /* this is not comment too ! \\\n" + ".............. */ ttt \";\n" + " global.b = b; \n" + "}(global);\n" + "///</module>"; final Pattern pattern = Pattern.compile(regex, Pattern.MULTILINE | Pattern.DOTALL); 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