How to replace some character in mysql column by 'x'? - php

Question

I have emails like this
uuak6G6GgD#gmail.com
d3lferM#gmail.com
Efqc9#gmail.com
How to convert and select like this.
uuakxxxxxx#xxxxx.xxx
d3lfxxx#xxxxx.xxx
Efqcx#xxxxx.xxx
Yes I am able to get this value but, I am not good enough in mysql function so please help me to make it simple and short if possible. And also suggest what other solution would be to make it.
I have created my query as
SELECT CONCAT(LEFT(email,
4),SUBSTR(REGEXP_REPLACE(email,'[a-z0-9]',"x"),5)),email
FROM `users`
I am using PHP as server side, so If we could involve php to make good enough, please also suggest.
Your help and suggestions are heartily appreciable.

Answer 1

If the point is obfuscation of email addresses, then you should not replace the characters by x, thus giving indication on the length of the email address. Just take the first 4 characters (left() function) and add a fixed ending of "xxxxxxxx#xxxx.xxx". You also need to decide how to handle email addresses where the user part is shorter than 4 characters.

Answer 2

If you want to achieve this using PHP you can simply use the following regex along with preg_replace function like as
(^(\w){1,4}|#|\.)(*SKIP)(*F)|(.)
Example :
echo preg_replace("/(^(\w){1,4}|#|\.)(*SKIP)(*F)|(.)/","$1x","uuak6G6GgD#gmail.com");

Answer 3

I would suggest something like :
$email = substr($email, 0, 4) . preg_replace('/\w/', 'x', substr($email, 4));
Doing it in the MySQL query is usually not reasonnable imo. MySQL isn't very good at that kind of data transformation.

Answer 4

$emails = [
'uuak6G6GgD#gmail.com',
'd3lferMGo7#gmail.com',
'Efqc90dUGI#gmail.com',
'I#gmail.com',
];
$modded = [];
foreach ($emails as $item) {
$name = explode('#', $item);
$name = str_pad(substr($name[0], 0, 4), 4, "x");
$modded[] = $name . 'xxxx#xxx.xxx';
}
var_dump($modded);

Answer 5

involve php, select record and than
Break every email address in two parts
$email = 'I#gmail.com';
$email = explode('#', $email);
$firstPart = $email[0];
$lastPart = $email[1];
$first4 = substr($firstPart, 0, 4);
$mid = preg_replace('/[^.#\-]/', 'x', substr($firstPart, 4));
$last = preg_replace('/[^.#\-]/', 'x', $lastPart);
$converted = $first4.$mid.'#'.$last;