<?php
$refNumbers = array('C28', 'C29');
$partIds = array('1AB010050093', '1AB008140029');
$combined = array();
foreach($refNumbers as $index => $refNumber) {
if(!array_key_exists($index, $partIds)) {
throw OutOfBoundsException();
}
$combined[] = array(
'ref' => $refNumber,
'part' => $partIds[$index]
);
}
print_r($combined);