regexp to partly hide email? [closed]

Answer 1

A replacement callback is an option.

echo preg_replace_callback('/(?<=^.).+(?=@)/u', function($match) {
    return str_pad('', strlen($match[0]), '*');
}, "something@something.com");
//s*******@something.com

Note I use an anonymous function as the callback - this is PHP >= 5.3 only. If you're on < 5.3, use a named function or one created with function_create().