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php - 对 foreach 结果进行排序

问题描述

我有一个 foreach 循环，我想按距离对结果进行排序。

foreach ($this->items as $i => $item) {

            $latitudeFrom = 123;
            $longitudeFrom = 123;

            $theta = $longitudeFrom - $this->item->longitude;
            $dist = sin(deg2rad($latitudeFrom)) * sin(deg2rad($this->item->latitude)) +  cos(deg2rad($latitudeFrom)) * cos(deg2rad($this->item->latitude)) * cos(deg2rad($theta));
            $dist = acos($dist);
            $dist = rad2deg($dist);
            $miles = $dist * 60 * 1.1515;
            $distance = $miles * 1.609344;
}

echo $distance;

我想按$distance. 如何才能做到这一点？

标签： phparraysloopssorting

解决方案

$latitudeFrom = 123;
$longitudeFrom = 123;

usort($this->items, function ($item1, $item2) use ($latitudeFrom, $longitudeFrom) {
    $distance1 = acos(rad2deg(sin(deg2rad($latitudeFrom)) * sin(deg2rad($item1->latitude)) +  cos(deg2rad($latitudeFrom)) * cos(deg2rad($item1->latitude)) * cos(deg2rad($longitudeFrom - $item1->longitude)))) * 60 * 1.1515 * 1.609344;

    $distance2 = acos(rad2deg(sin(deg2rad($latitudeFrom)) * sin(deg2rad($item2->latitude)) +  cos(deg2rad($latitudeFrom)) * cos(deg2rad($item2->latitude)) * cos(deg2rad($longitudeFrom - $item2->longitude)))) * 60 * 1.1515 * 1.609344;

    $result = 0;
    if ($distance1 < $distance2) {
        $result = -1;
    } else if ($distance1 > $distance2) {
        $result = 1;
    }

    return $result;
});

$this->items现在已排序。要颠倒顺序，只需切换<and >。

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