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
Processing...

Test String

Code Generator

Language

Generated Code

$re = '/\b"{0,1}[A-Z0-9_][A-Z0-9._%+-]*[A-Z0-9_]\@(?![. \-])(([A-Z0-9-]+\.)+[A-Z]{2,8}|\[{0,1}(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])\.(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])\.(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])\.(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])\]{0,1})\b/i'; $str = 'invalid formats cf+2@3465456rteyaesrgrdsfgsdfg@thefloow.com @@@ Leading dot in address eg .cf@thefloow.com Trailing dot in address eg cf+.@thefloow.com Multiple dots eg cf+..1@thefloow.com Leading dash in front of domain eg cf@-thefloow.com invalid top level domain names eg cf@thefloow.web Multiple dots in the domain portion cf@thefloow..com plainaddress Missing @ sign and domain #@%^%#$@#$@#.com Garbage @domain.com Missing username Joe Smith <email@domain.com> Encoded html within email is invalid email.domain.com Missing @ email@domain@domain.com Two @ sign .email@domain.com Leading dot in address is not allowed email.@domain.com Trailing dot in address is not allowe email..email@domain.com Multiple dots あいうえお@domain.com Unicode char as address email@domain.com (Joe Smith) Text followed email is not allowed email@domain Missing top level domain (.com/.net/.org/etc) email@-domain.com Leading dash in front of domain is invalid email@domain.web .web is not a valid top level domain email@111.222.333.44444 Invalid IP format email@domain..com Multiple dot in the domain portion is invalid plainaddress #@%^%#$@#$@#.com @example.com Joe Smith <email@example.com> email.example.com email@example@example.com .email@example.com email.@example.com email..email@example.com あいうえお@example.com email@example.com (Joe Smith) email@example email@-example.com email@example.web email@111.222.333.44444 email@111.222.333.244 email@01.222.233.244 email@example..com Abc..123@example.com “(),:;<>[\\]@example.com just"not"right@example.com this\\ is"really"not\\allowed@example.com valid formats ip address as domain name eg cf@192.168.0.1 quoted strings eg "cf"@thefloow.com email@domain.com Valid email firstname.lastname@domain.com Email contains dot in the address field email@subdomain.domain.com Email contains dot with subdomain firstname+lastname@domain.com Plus sign is considered valid character email@123.123.123.123 Domain is valid IP address email@[123.123.123.123] Square bracket around IP address is considered valid "email"@domain.com Quotes around email is considered valid 1234567890@domain.com Digits in address are valid email@domain-one.com Dash in domain name is valid _______@domain.com Underscore in the address field is valid email@domain.name .name is valid Top Level Domain name email@domain.co.jp Dot in Top Level Domain name also considered valid (use co.jp as example here) firstname-lastname@domain.com Dash in address field is valid email@example.com firstname.lastname@example.com email@subdomain.example.com firstname+lastname@example.com email@123.123.123.0 email@[123.123.0.123] email@123.0.123.123 email@[0.123.123.123] “email”@example.com 1234567890@example.com email@example-one.com _______@example.com email@example.name email@example.museum email@example.co.jp 3465456rteyaesrgrdsfgsdfg@thefloow.com firstname-lastname@example.com much.“more\\ unusual”@example.com very.unusual.“@”.unusual.com@example.com very.“(),:;<>[]”.VERY.“very@\\\\ "very”.unusual@strange.example.com'; preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0); // Print the entire match result var_dump($matches);

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 PHP, please visit: http://php.net/manual/en/ref.pcre.php