$string = simplexml_load_file('http://img.ignio.com/r/export/utf/xml/weekly/cur.xml');

$zodiac = [
    'aries' => 'Овен',
    'taurus' => 'Телец',
    'gemini' => 'Близнецы',
    'cancer' => 'Рак',
    'leo' => 'Лев',
    'virgo' => 'Дева',
    'libra' => 'Весы',
    'scorpio' => 'Скорпион',
    'sagittarius' => 'Стрелец',
    'capricorn' => 'Козерог',
    'aquarius' => 'Водолей',
    'pisces' => 'Рыбы',
];

$result = '';

foreach($string as $key => $value) {
    if (!empty($value->business) and !empty($zodiac[$key])) {
        $result .= $zodiac[$key] . "\n" . $value->business . "\n";
    }
}
$result .= 'По материалам сайта www.ignio.com';
$file_path = '/Users/Uncater/Desktop/stars.txt';
if (file_exists($file_path)) {
    file_put_contents($file_path, $result);
}