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

r"
"
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 = "^[1-9]\\d{0,3} ?[a-zA-Z]?(?: ?[/-] ?[1-9]\\d{0,3} ?[a-zA-Z]?)?$"; final String string = "############# valid ##########\n" + "12\n" + "12a\n" + "12A\n" + "12 A\n" + "12 a\n" + "12 b\n" + "12 z\n" + "121 b\n" + "56/58\n" + "56/58a\n" + "56-58\n" + "56 - 58\n" + "56-58a\n" + "1234\n" + "1234 a\n\n" + "56/58a\n" + "18a - 19b\n" + "18a-19b\n\n\n" + "############# not valid ##########\n" + "12345\n" + "25-ab\n" + "12ü\n" + "12_\n" + "asdfghjklöqwertzuioyxcvbnm\n" + "12!\"§$$%&/()\n" + "a2\n" + " a2\n" + "13àâäèéêë\n" + "0\n" + "123aaa123, \n" + "123 aaa 123 \n" + "1 a 1 \n" + "1a 1' \n" + "1a1 \n" + "13àâäèéêë\n" + "00 a\n" + "a a\n" + "00a\n" + "0a\n" + "12 ab 12"; 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