- var_dump: documentation ( source)
- preg_replace_callback: documentation ( source)
- str_repeat: documentation ( source)
- substr_replace: documentation ( source)
<?php
function callback($s) {
return substr_replace($s[0], str_repeat('*', strlen($s[0])), 0, -4);
}
$value = '5746244234383238';
var_dump(preg_replace_callback('/\d{12,16}/', 'callback', $value));