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 = "(?:<[^>]*>)?(accessed(?:\\s*\\:?\\s*| on ))((?:[0-2]?[0-9]?|30|31)(?:st|nd|rd|th)?)(?:<\\/[^>]*>)?([\\.\\-\\/ ])(Jan(?:uary)?|Feb(?:ruary)?|Mar(?:ch)?|Apr(?:il)?|May|June?|July?|Aug(?:ust)?|Sep(?:tember)?|Oct(?:ober)?|Nov(?:ember)?|Dec(?:ember)?|[1-9]|1[012])([\\.\\-\\/ ])(?:<[^>]*>)?(20\\d{2})(?:<\\/[^>]*>)?"; final String string = "<note>accessed 13</note> March <year>2022</year>\n" + "<note>accessed 13th</note> March <year>2022</year>\n" + " <note>accessed 8</note> April <year>2022</year>.\n" + "accessed 21st February 2020\n" + "accessed 32 Febr 2022\n" + "accessed 32 February 2022\n" + "accessed 30 February 202\n" + "accessed 30 January 2022\n" + "accessed 30 Jan 2022\n" + "accessed 30 February 2022\n" + "accessed 30 Feb 2022\n" + "accessed: 30 March 2022\n" + "accessed on 30 Mar 2022\n" + "accessed 30 April 2022\n" + "accessed 30 Apr 2022\n" + "accessed 30 May 2022\n" + "accessed 30 June 2022\n" + "accessed 30 Jun 2022\n" + "accessed 30 July 2022\n" + "accessed 30 Jul 2022\n" + "accessed 30 August 2022\n" + "accessed 30 Aug 2022\n" + "accessed 30 September 2022\n" + "accessed 30 Sep 2022\n" + "accessed 30 October 2022\n" + "accessed 30 Oct 2022\n" + "accessed 30 November 2022\n" + "accessed 30 Nov 2022\n" + "accessed 30 December 2022\n" + "accessed 30 Dec 2022\n\n" + "accessed on 30.12.2022\n" + "accessed on 30.13.2022\n" + "accessed on 34.12.2022\n" + "accessed on 30.12.2023\n" + "accessed on 30.15.2022\n" + "accessed on 01.12.2022\n" + "accessed on 41.12.2092\n\n" + "accessed on 30-12-2022\n" + "accessed on 30-13-2022\n" + "accessed on 34-12-2022\n" + "accessed :30-12-2023\n" + "accessed :30-15-2022\n" + "accessed :01-12-2022\n" + "accessed :41-12-2092\n\n" + "accessed : 30/12/2022\n" + "accessed : 30/13/2022\n" + "accessed :34/12/2022\n" + "accessed :30/12/2023\n" + "accessed : 30/15/2022\n" + "accessed 01/12/2022\n" + "accessed 41/12/2092\n\n\n\n\n\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