- print_r: documentation ( source)
- array_merge: documentation ( source)
- array_diff: documentation ( source)
<?php
$a = [
"foo",
"bar",
"baz",
"test"
];
$b = [
"foo",
"bar",
"a"
];
$res = array_merge(array_diff($a, $b), array_diff($b, $a));
print_r($res);