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

/
/
g

Test String

Code Generator

Generated Code

import java.util.regex.Matcher; import java.util.regex.Pattern; public class Example { public static void main(String[] args) { final String regex = "(([^<>()\\[\\]\\.,;:\\s@\\\"]+(\\.[^<>()\\[\\]\\.,;:\\s@\\\"]+)*)|(\\\".+\\\"))@(([^<>()\\.,;\\s@\\\"]+\\.{0,1})+([^<>()\\.,;:\\s@\\\"]{2,}|[\\d\\.]+))"; final String string = "- VALID MAILS\n\n" + "Abc@example.com\n" + "Abc@example.com.\n" + "Abc@10.42.0.1\n" + "user@localserver\n" + "Abc.123@example.com\n" + "user+mailbox/department=shipping@example.com\n" + "\"very.(),:;<>[]\\\".VERY.\\\"very@\\\\ \\\"very\\\".unusual\"@strange.example.com\n" + "!#$%&'*+-/=?^_`.{|}~@example.com\n" + "\"()<>[]:,;@\\\\\\\"!#$%&'-/=?^_`{}| ~.a\"@example.org\n" + "\"Abc@def\"@example.com\n" + "\"Fred Bloggs\"@example.com\n" + "\"Joe.\\\\Blow\"@example.com\n" + "Loïc.Accentué@voilà.fr\n" + "\" \"@example.org\n" + "user@[IPv6:2001:DB8::1]\n\n" + "- INVALID MAILS\n\n" + "Abc.example.com\n" + "A@b@c@example.com\n" + "a\"b(c)d,e:f;g<h>i[j\\k]l@example.com\n" + "just\"not\"right@example.com\n" + "this is\"not\\allowed@example.com\n" + "this\\ still\\\"not\\\\allowed@example.com\n" + "john..doe@example.com\n" + "john.doe@example..com"; final Pattern pattern = Pattern.compile(regex); 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