- array_map: documentation ( source)
- print_r: documentation ( source)
- explode: documentation ( source)
- trim: documentation ( source)
<?php
$names = ["barira, stefan",
"cikka, maria",
"luppo, martin ",
"bill, sebastian"];
$result = array_map(function($v) {
$a = explode(',', $v);
return trim($a[1]).', '.trim($a[0]);
}, $names);
print_r($result);