---

<?php
$dom = new DOMDocument('1.0', 'UTF-8');
$root = $dom->createElement('cities');
$dom->appendChild($root);

$cities = [
    ['id'=>1,'name'=>'Москва','country'=>'Россия','population'=>12678079],
    ['id'=>2,'name'=>'СПб','country'=>'Россия','population'=>5398064]
];

foreach($cities as $c){
    $city = $dom->createElement('city');
    $city->setAttribute('id',$c['id']);
    $city->appendChild($dom->createElement('name',$c['name']));
    $city->appendChild($dom->createElement('country',$c['country']));
    $city->appendChild($dom->createElement('population',$c['population']));
    $root->appendChild($city);
}

$dom->save('cities.xml');
echo "XML создан\n";
?>