- strtolower: documentation ( source)
<?php
$value = 'Österreich';
$country = strtolower($value);
switch ($country) {
case 'deutschland':
case 'de':
echo "de";
break;
case 'österreich':
case 'at':
case 'oesterreich':
echo "at";
break;
default:
throw new Exception('Invalid country: ' . $value);
break;
}