輕微問題與使用

Question

有一個輕微的問題，讓我的陣列適合Distance sory。我雖然使用usort可以做到這一點，但我顯然錯了？

usort

usort($return, function($a, $b){ 
    $t1 = $a['Distance']; 
    $t2 = $b['Distance']; 
    return $t1 - $t2; 
}); 

$return生產：

Array 
(
[0] => Array 
    (
     [ZipCode] => 06096 
     [Distance] => 0 
    ) 

[1] => Array 
    (
     [ZipCode] => 06096 
     [Distance] => 0 
    ) 

[2] => Array 
    (
     [ZipCode] => 06026 
     [Distance] => 3.16 
    ) 

[3] => Array 
    (
     [ZipCode] => 06080 
     [Distance] => 4.14 
    ) 

[4] => Array 
    (
     [ZipCode] => 06080 
     [Distance] => 4.14 
    ) 

[5] => Array 
    (
     [ZipCode] => 06078 
     [Distance] => 4.14 
    ) 

[6] => Array 
    (
     [ZipCode] => 06064 
     [Distance] => 3.6 
    ) 

[7] => Array 
    (
     [ZipCode] => 06028 
     [Distance] => 3.6 
    ) 

[8] => Array 
    (
     [ZipCode] => 06028 
     [Distance] => 3.6 
    ) 

[9] => Array 
    (
     [ZipCode] => 06006 
     [Distance] => 4.83 
    ) 

[10] => Array 
    (
     [ZipCode] => 06095 
     [Distance] => 4.83 
    ) 

[11] => Array 
    (
     [ZipCode] => 06095 
     [Distance] => 4.83 
    ) 

[12] => Array 
    (
     [ZipCode] => 06006 
     [Distance] => 4.83 
    ) 

) 

Answer 1

您在使用距離任何strtotime原因？

這應該工作：

usort($return, function($a, $b){ 
    return $a['Distance'] - $b['Distance']; 
}); 

編輯：

好吧，我看到的問題是什麼，寫在the doc：

從比較返回非整數值函數（如float）將導致內部轉換爲回調的返回值的整數。因此，諸如0.99和0.1之類的值都將被轉換爲0的整數值，這將比較這些值相等。

因此，解決辦法是，以確保比較函數總是返回一個整數：

usort($return, function($a, $b){ 
    $t1 = $a['Distance']; 
    $t2 = $b['Distance']; 
    if ($t1 == $t2) return 0; 
    return $t1 < $t2 ? -1 : 1; 
});