Preg Match Email Address

[Kerant]

Hi there,

I was looking around on the PHP Manual for a preg match string that would validate an email address in a form, and came across this:

PHP Code:

If you need to check for .com.br and .com.au and .uk and all the other crazy domain endings i found the following expression works well if you want to validate an email address. Its quite generous in what it will allow

<?php

        $email_address = "phil.taylor@a_domain.tv";

    if (preg_match("/^[^@]*@[^@]*\.[^@]*$/", $email_address)) {
        return "E-mail address";       
    }
       
?>

This string works really well it seems, but I was just wondering if somebody could explain what it is actually doing (the string "/^[^@]*@[^@]*\.[^@]*$/")?

I'm eager to understand how it works and I can't seem to find a decent enough tutorial.

Thanks very much.

[NogDog]

You might want to take a look at this article before settling for that particular regexp solution.

[sfullman]

I concur, that's a pretty sorry regex for email matching you could get away with murder on that, in fact this string

PHP Code:

@.


would work :-~ - and it would fail for domains like @sub.domain.com

"/^[^@]*@[^@]*\.[^@]*$/" basically means:

start of string
anything besides @ "maybe"
an @
anything besides @ "maybe"
one period
anything besides @ "maybe"

yuck..

here's what I use:

PHP Code:

function valid_email($x){
    if(preg_match('/^[_a-zA-Z0-9-]+(\.[_a-zA-Z0-9-]+)*@[a-zA-Z0-9-]+(\.[a-zA-Z0-9-]+)+$/',$x))return true;
    return false;
}


[Kerant]

Originally Posted by sfullman

here's what I use:

PHP Code:

function valid_email($x){
    if(preg_match('/^[_a-zA-Z0-9-]+(\.[_a-zA-Z0-9-]+)*@[a-zA-Z0-9-]+(\.[a-zA-Z0-9-]+)+$/',$x))return true;
    return false;
}


Ah that looks good. Could you briefly explain how it works please?

Thanks for the replies!

[sfullman]

I couldn't sleep with myself at night knowing I'd denied a newbie their fundamental right to research and learning. NogDog's link above actually shows my function would fail under some cases, so study that but also look up some regex tutorials which there are many online

cheers mate

[NogDog]

In case you've not yet found these pages in the manual:
Pattern Syntax
Pattern Modifiers