- array_reduce: documentation ( source)
- implode: documentation ( source)
- in_array: documentation ( source)
<?php
$itinerary = array (array('portName'=>'Day At Sea'), array('portName'=>'Moscow'));
$badPorts = array('At Sea', 'Day At Sea', 'Cruising The Mediterranean Sea');
$image = '';
$image .= implode(',', array_reduce($itinerary,
function ($result, $item) use (&$index, $badPorts) {
if(!in_array($item['portName'], $badPorts)) $result[$index] = $item['portName'];
$index++;
return $result;
}));