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

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 = "^([+-]?\\d*((([02468][048]|[13579][26]|\\d\\d(?!00))([02468][048]|[13579][26]))|\\d{4}(?!-02-29|-366))-((?!02-3|(0[469]|11)-31|000)((0[1-9]|1[012])-(0[1-9]|[12]\\d|30|31)|([012]\\d\\d|3([0-5]\\d|6[0-6])))|(W(?!00)([0-4]\\d|51|52)-[1-7]))|((\\+?\\d*([02468][048]|[13579][26])|-\\d*([02468][159]|[13579][37]))(04|09|15|20|26|32|37|43|48|54|60|65|71|76|82|88|93|99)|(\\+?\\d*([02468][159]|[13579][37])|-\\d*([02468][26]|[13579][048]))(05|11|16|22|28|33|39|44|50|56|61|67|72|78|84|89|95)|(\\+?\\d*([02468][26]|[13579][048])|-\\d*([02468][37]|[13579][159]))(01|07|12|18|24|29|35|40|46|52|57|63|68|74|80|85|91|96)|\\+?\\d*(([02468][37]|[13579][159])(03|14|20|25|31|36|42|53|59|64|70|76|81|87|92|[049]8))|-\\d*(([02468][048]|[13579][26])([059]2|08|13|19|24|30|36|41|47|58|64|69|75|80|86|97)))-W53-[1-7])$"; final String string = "2015-08-10\n" + "2015-10-08\n" + "12015-08-10\n" + "-2015-08-10\n" + "+2015-08-10\n" + "0015-08-10\n" + "1582-10-10\n" + "2015-02-28\n" + "2016-02-29\n" + "2000-02-29\n" + "0000-02-29\n" + "-2000-02-29\n" + "-2016-02-29\n" + "200000-02-29\n" + "2016-366\n" + "2000-366\n" + "0000-366\n" + "-2016-366\n" + "-2000-366\n" + "2015-081\n" + "2015-W33-1\n" + "2015-W53-7\n" + " 2015-08-10 \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