- array_intersect_key: documentation ( source)
- print_r: documentation ( source)
- array_flip: documentation ( source)
<?php
$keys = ['a','b','c','d','e','f','g','h','i','alias'];
$private = ['a','b','c','d','real'];
$aliases = [
'alias' => 'real'
];
$aliases = array_flip($aliases);
print_r(array_intersect_key($aliases, array_flip($private)));