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 = "(?xi)^(\n" + "(AT)?U[0-9]{8} | # Austria\n" + "(BE)?0[0-9]{9} | # Belgium\n" + "(BG)?[0-9]{9,10} | # Bulgaria\n" + "(HR)?[0-9]{11} | # Croatia\n" + "(CY)?[0-9]{8}L | # Cyprus\n" + "(CZ)?[0-9]{8,10} | # Czech Republic\n" + "(DE)?[0-9]{9} | # Germany\n" + "(DK)?[0-9]{8} | # Denmark\n" + "(EE)?[0-9]{9} | # Estonia\n" + "(EL|GR)?[0-9]{9} | # Greece\n" + "ES[A-Z][0-9]{7}(?:[0-9]|[A-Z]) | # Spain\n" + "(FI)?[0-9]{8} | # Finland\n" + "(FR)?[0-9A-Z]{2}[0-9]{9} | # France\n" + "(GB)?([0-9]{9}([0-9]{3})?|[A-Z]{2}[0-9]{3}) | # United Kingdom\n" + "(HU)?[0-9]{8} | # Hungary\n" + "(IE)?[0-9]S[0-9]{5}L | # Ireland\n" + "(IT)?[0-9]{11} | # Italy\n" + "(LT)?([0-9]{9}|[0-9]{12}) | # Lithuania\n" + "(LU)?[0-9]{8} | # Luxembourg\n" + "(LV)?[0-9]{11} | # Latvia\n" + "(MT)?[0-9]{8} | # Malta\n" + "(NL)?[0-9]{9}B[0-9]{2} | # Netherlands\n" + "(PL)?[0-9]{10} | # Poland\n" + "(PT)?[0-9]{9} | # Portugal\n" + "(RO)?[0-9]{2,10} | # Romania\n" + "(SE)?[0-9]{12} | # Sweden\n" + "(SI)?[0-9]{8} | # Slovenia\n" + "(SK)?[0-9]{10} # Slovakia\n" + ")$"; final String string = "ATU99999999\n" + "BE0999999999\n" + "BG999999999\n" + "HR12345678901\n" + "CY99999999L\n" + "CZ12345678\n" + "DK99999999\n" + "EE123456789\n" + "FI99999999\n" + "FRXX999999999\n" + "DE999999999\n" + "EL123456789\n" + "HU12345678\n" + "IE1S23456L\n" + "IE1234567T\n" + "IE1234567TW\n" + "IE1234567FA\n" + "ESA12345678\n" + "ESZ1234567E"; 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