i want to input the country code like "fr" and get the largest city "paris" , and if possible also the continent, in PHP !
Extend to your needs, I already added the city you asked for:
$largest = [
'fr' => 'paris',
];
$code = 'fr';
echo $largest[$code];
You can further improve this by wrapping it into a class supporting ArrayAccess
giving a default value in case it does not exist.