Phpml lib (KMeans) clustering

<?php
require_once __DIR__ . '/vendor/autoload.php';

use Phpml\Clustering\KMeans;

$locations = file('results.csv');
foreach ($locations as &$line) {
    $row = explode(',', $line);
    $line = [(float) $row[0], (float) $row[1]];
}


$clusterer = new KMeans(18);
$clusters = $clusterer->cluster($locations);
$lines = [];
foreach ($clusters as $key => $cluster) {
    foreach ($cluster as $sample) {
        $lines[] = sprintf('%s;%s;%s', $key, $sample[0], $sample[1]);
    }
}
file_put_contents('results-clusters.csv', implode(PHP_EOL, $lines));