我從陣列中的數據庫中獲得了用戶的經緯度

我有我的經緯

現在,我要計算距離并使用該距離對數據庫中的用戶進行排序

$mylat = $_SESSION['lat'];

$mylng = $_SESSION['lng'];

$statement = $pdo->prepare("SELECT * FROM users");

$statement->execute();

$users = $statement->fetchAll();

foreach($users as $row){

$dist = 0.0;

$x1 = $mylng;

$x2 = $row['lng'];

$y1 = $mylat;

$y2 = $row['lat'];

$dist = acos(sin($x1=deg2rad($x1))*sin($x2=deg2rad($x2))+cos($x1)*cos($x2)*cos(deg2rad($y2) - deg2rad($y1)))*(6378.137);

$distn = FLOOR ( ROUND($dist,1) * 2 ) / 2 ;

}

sort($distn);

foreach ($users as $row) {

$dist = 0.0;

$x1 = $mylng;

$x2 = $row['lng'];

$y1 = $mylat;

$y2 = $row['lat'];

$dist = acos(sin($x1=deg2rad($x1))*sin($x2=deg2rad($x2))+cos($x1)*cos($x2)*cos(deg2rad($y2) - deg2rad($y1)))*(6378.137);

$distn = FLOOR ( ROUND($dist,1) * 2 ) / 2 ;

echo $row['username'];

echo $distn;

}

因此,在第一個foreach中,我計算了每個用戶到我的距離.

比我想對與我的距離后的用戶進行排序并顯示它們

那里有我的名字,也有我的距離.

user1 0.5km distance

user2 1km distance

但是我不會工作.

謝謝你的幫助 ：)

解決方法:

創建一個距離函數：

function getDistance ($lat, $lon)

{

global $mylng, $mylat;

$x1 = deg2rad($mylng);

$x2 = deg2rad($lon);

$y1 = deg2rad($mylat);

$y2 = deg2rad($lat);

$dist = acos(sin($x1)*sin($x2)+cos($x1)*cos($x2)*cos($y2 - $y1))*(6378.137);

return $dist;

}

創建一個比較函數：

function compareDistance ($user1, $user2)

{

return getDistance ($user1['lat'], $user1['lng']) - getDistance ($user2['lat'], $user2['lng']);

}

然后,您可以通過uasort傳遞數組：

uasort ($users, 'compareDistance');

編輯：

您的程序可以被重寫：

function getDistance ($lat, $lon)

{

global $mylng, $mylat;

$x1 = deg2rad($mylng);

$x2 = deg2rad($lon);

$y1 = deg2rad($mylat);

$y2 = deg2rad($lat);

$dist = acos(sin($x1)*sin($x2)+cos($x1)*cos($x2)*cos($y2 - $y1))*(6378.137);

return $dist;

}

function compareDistance ($user1, $user2)

{

return getDistance ($user1['lat'], $user1['lng']) - getDistance ($user2['lat'], $user2['lng']);

}

$mylat = $_SESSION['lat'];

$mylng = $_SESSION['lng'];

$statement = $pdo->prepare("SELECT * FROM users");

$statement->execute();

$users = $statement->fetchAll();

uasort ($users, 'compareDistance');

foreach ($users as $row) {

$dist = getDistance ($row['lat'], $row['lng']);

$distn = floor(round($dist,1) * 2) / 2 ;

echo $row['username']. ": " . $distn . "km distance";

}

標簽：php,arrays,sorting,floating-point

來源： https://codeday.me/bug/20191012/1902470.html

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