Problem validating e-mail with RegEx using preg_match() in PHP

Question

I can't get working a preg_match() in PHP to validate an e-mail address. I've tested the RegEx expression that I've found on Internet with the http://www.regexer.com tool and works fine with the same input I'm using on my PHP application.

RegEx expression:

^([a-z0-9\+_\-]+)(\.[a-z0-9\+_\-]+)*@([a-z0-9\-]+\.)+[a-z]{2,6}$

Regexer: http://regexr.com?2sr2a

And I'm applying it like this in PHP:

$email   = "local@test.com";
$pattern = "/^([a-z0-9\+_\-]+)(\.[a-z0-9\+_\-]+)*@([a-z0-9\-]+\.)+[a-z]{2,6}$/ix";

if (false == preg_match($pattern, $email))
    echo "false";

And of course, I get a false with this e-mail and others that I've tested. The expression I think is well formed because on regexer I can test and it works. What I'm applying incorrectly?

Thank you in advance!

[Gazillion duplicates](http://stackoverflow.com/search?q=validate+email+php) - use PHP's native `filter_var` instead of a regex — Gordon, Jan 04 '11 at 16:45
@Kobi/@bisko: Probably depends on PHP version/configuration? Escaping the \ works on my environment. — ipalaus, Jan 04 '11 at 16:46
possible duplicate of [Validate Email in php](http://stackoverflow.com/questions/3499192/validate-email-in-php) — Gordon, Jan 04 '11 at 16:46

score 1 · Accepted Answer · answered Jan 04 '11 at 16:46

1

Backslash characters need to be properly escaped by doubling them like this:

$pattern = "/^([a-z0-9\\+_\\-]+)(\\.[a-z0-9\\+_\\-]+)*@([a-z0-9\\-]+\\.)+[a-z]{2,6}$/ix";

Using this pattern, preg_match correctly returns 1.

answered Jan 04 '11 at 16:46

SirDarius

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They don't normally. Backslashes are only stripped when they preceed another backslash, double quote, $, octal literals, or one of the ascii escapes \r \n \t. `print "\."` will print `\.` – mario Jan 04 '11 at 16:50
Although it's not mandatory to escape backslashes, it is highly recommended to do so in double-quoted strings, especially if you might accidentally insert a character causing the creation of a valid escape sequence. – SirDarius Jan 04 '11 at 17:03

score 0 · Answer 2 · answered Jan 04 '11 at 16:46

I am not sure what is wrong in your code but here you have a fully functional php function for checking an email address:

function is_validemail($email) 
{
     return preg_match('/^[\w.-]+@([\w.-]+\.)+[a-z]{2,6}$/is', $email);
}

$email = "local@root.ws";

if(is_validemail($email)) { echo ("email validated"); } else { echo ("invalid email given"); }

Hope it helps!

Problem validating e-mail with RegEx using preg_match() in PHP

2 Answers2