多个结果的总和

I'm trying to make a simple script that visualizes runtastic data but I'm having a little problem. I run the following script, which only displays the latest activity.

$myRuntasticActivities = $runtastic->getActivities(null, null, 2017);
$distanceKM = $myRuntasticActivities[0]->distance / 1000;
echo "In 2017 I ran $distanceKM KM";

Result output: In 2017 I ran 6,8KM.

If I change the [0] to [1] I get the second most recent activity. How can I add all results up? I believe the runtastic script is limited to showing the latest 419 results. Is there a way to add 0 -> 419?

I've tried array_sum, but I can't get it to work.

You can use array_reduce.

$sum = array_reduce($myRuntasticActivities, function($carry, $item){
    return $carry + $item->distance;
}, 0) / 1000;

You could use a foreach.

$sum = 0;
foreach ($myRuntasticActivities as $act) {
    $sum += $act->distance / 1000;
}

You could use a simple for.

$sum = 0;
for ($i = 0; $i < count($myRuntasticActivities); $i++) {
    $sum += $myRuntasticActivities[$i]->distance / 1000;
}