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 = "(((20[012]\\d|19\\d\\d)|(1\\d|2[0123]))-((0[0-9])|(1[012]))-((0[1-9])|([12][0-9])|(3[01])))|(((0[1-9])|([12][0-9])|(3[01]))-((0[0-9])|(1[012]))-((20[012]\\d|19\\d\\d)|(1\\d|2[0123])))|(((20[012]\\d|19\\d\\d)|(1\\d|2[0123]))\\/((0[0-9])|(1[012]))\\/((0[1-9])|([12][0-9])|(3[01])))|(((0[0-9])|(1[012]))\\/((0[1-9])|([12][0-9])|(3[01]))\\/((20[012]\\d|19\\d\\d)|(1\\d|2[0123])))|(((0[1-9])|([12][0-9])|(3[01]))\\/((0[0-9])|(1[012]))\\/((20[012]\\d|19\\d\\d)|(1\\d|2[0123])))|(((0[1-9])|([12][0-9])|(3[01]))\\.((0[0-9])|(1[012]))\\.((20[012]\\d|19\\d\\d)|(1\\d|2[0123])))|(((20[012]\\d|19\\d\\d)|(1\\d|2[0123]))\\.((0[0-9])|(1[012]))\\.((0[1-9])|([12][0-9])|(3[01])))"; final String string = "work:\n" + "2022-01-01\n" + "01-01-2020\n" + "1990/01/01\n" + "12/30/2020\n" + "30/12/2020\n" + "30.12.2020\n" + "2020.12.30\n" + "19-12-30\n" + "30-12-19\n" + "2020/12/30\n" + "12/30/19\n" + "30/12/19\n" + "30.12.19\n" + "19.12.30\n\n" + "not work:\n" + "1022-01-01\n" + "01-15-2020\n" + "2990/01/01\n" + "13/30/2020\n" + "30/13/2020\n" + "30.12.9029\n" + "2020.14.30\n" + "2020.12.33\n" + "19-12-33\n" + "19-13-30\n" + "33-12-19\n" + "30-12-35\n" + "2020/13/30\n" + "2020/12/34\n" + "12/30/29\n" + "30/12/29\n" + "30.12.26\n" + "30.12.30\n" + "13/30/19\n" + "30/13/19\n" + "30.13.19\n" + "19.13.30\n" + "12/33/19\n" + "33/12/19\n" + "33.12.19\n" + "19.12.33\n" + "1/1/19\n" + "1/01/19\n" + "01/1/19\n" + "1/01/2019\n" + "1/1/2019\n" + "01/1/2019\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