如何使用PHP部分屏蔽/隐藏电子邮件地址

Question

Im trying to achieve the following with PHP

[e-mail]           => s*****@gmail.com
[e-mail]               => **@yahoo.com
[e-mail]  => samplead*****@hotmail.com

I want to hide last five characters in the portion that stays before '@'

I can write long code to do this by splitting and then replacing based on lengths, but Im sure there must be an easy way to do this using PHP functions, any help please?

UPDATE:
Im adding my code here, Im sure its not efficient, and thats the reason Im asking it here

$email = '[e-mail]';
$star_string = '';
$expl_set = explode('@',$email);
if(strlen ($expl_set[0]) > 5){$no_stars = 5; }else{$no_stars = strlen ($expl_set[0]); }
for($i=0;$i<$no_stars; $i++)
{
    $star_string.='*'; 
}

$masked_email =  substr($expl_set[0], 0, -5).$star_string.'@'.$expl_set[1];

Answer 1

You can wrap it into a function, making it easier to call multiple times.

Basically, split the address and the domain, replace $mask number of characters in the end of the string (default 5) with *, or the length of the address if it's shorter than the amount of masked characters.

function mask_email($email, $masks = 5) {
    $array = explode("@", $email);
    $string_length = strlen($array[0]);
    if ($string_length < $masks)
        $masks = $string_length;
    $result = substr($array[0], 0, -$masks) . str_repeat('*', $masks);
    return $result."@".$array[1];
}

The above would be used like this

echo mask_email("[e-mail]")."
";
echo mask_email("[e-mail]");

which would ouput this

****@test.com
longer*****@test.com

You can also specify the number you want filtered by using the second parameter, which is optional.

echo mask_email("[e-mail]", 2); // Output: longerema**@test.com

Live demo