how to filter blacklisted domains out of email list

[stowoda]

Hi,
I wrote a little piece of code which I think is not a very good one. Please have a look:

$emaillist = array('[e-mail]','[e-mail]','[e-mail]');
$blacklisteddomains = ('keppler.com','gates.com');
$blacklistedemails =  filter_blacklisted($emaillist, $blacklisteddomains);

/** creates a list of blacklisted emails using a blacklisted domains list */
function filter_blacklisted($emaillist, $blacklisteddomains){
	$blacklistedemails = array();

foreach($emaillist as $email){
	foreach($blacklisteddomains as $domain){
		if(stripos($email,$domain)){
			array_push($blacklistedemails,$email);
		}
	}
}
return $blacklistedemails;
}

I don't think nesting foreach is necessary. Is there a faster or better way to do so?

Thanks for everyone who is helping me to think in the right direction!

Cheers,
Sto

[rsmith]

To see if the domains are in the array you can use the in_array() function. If it is... then you find the key of the blacklisted e-mail but using array_key() and then unset() the array key to remove it from the list.

[laserlight]

To see if the domains are in the array you can use the in_array() function.

One would have to extract the domain portion of the email address first.

I think that in terms of efficiency the implementation is fine. However, there is an oversight: suppose someone has the email address [e-mail]. Your code would blacklist that email address even though example.com is not a blacklisted domain name, simply because keppler.com is blacklisted.

[Horizon88]

I think the way I would do this would be something like this:

<?PHP
$blacklisted = array('@microsoft.com', '@ibm.com');
$emails = array('[e-mail]', '[e-mail]', '[e-mail]');
foreach ($emails as $email) {
    if (in_array(strstr($email, '@'), $blacklisted)) {
        // blacklisted domain
        echo 'blacklist'."\n";
    }
    else {
        // okay to go
        echo 'okay'."\n";
    }
}
?>

Edit: my bad, this'll just tell you what's blacklisted and what's not. You'd just array_push onto another array of blacklisted emails instead of echo 'blacklist', if that's what you wanted. I was just showing a way to do it without nesting the foreaches, and it shouldn't match something like [e-mail]