如何通過其中的特定值對數組進行排序？

Question

可能重複：
Sorting an array based on its value

我想排序它裏面的值的數組。我試過usort，但它導致了一些意想不到的結果，實際上改變了輸出的值，而不是僅僅移動數組中的元素。

下面是我要排序的數組：

Array 
(
[element1] => Array 
    (
     [Total] => 1 
     [paTotal] => 0 
     [totalPreregistrations] => 7 
     [totalPreregistrationsToDate] => 26 
     [pas] => Array 
      (
       [0] => Array 
        (
         [id] => 119 
        ) 

      ) 

    ) 

[element2] => Array 
    (
     [Total] => 1 
     [paTotal] => 0 
     [totalPreregistrations] => 0 
     [totalPreregistrationsToDate] => 58 
     [pas] => Array 
      (
       [0] => Array 
        (
         [id] => 107 
        ) 

      ) 

    ) 
... element3, 4, etc... 

我想通過「totalPreregistrations」號，以便在element2上面去，如果部件1 element2的的totalPreregistrations數排序進入上述部件1的。

當然，我也希望保留子數組。

謝謝！

Answer 1

Documentation: uasort()

function mySort($a, $b) { 
    if($a['totalPreregistrations'] == $b['totalPreregistrations']) { 
    return 0; 
    } else if($a['totalPreregistrations'] > $b['totalPreregistrations']) { 
    return 1; 
    } else { 
    return -1; 
    } 
} 

uasort($array, 'mySort'); 

Answer 2

您可以使用uasort代替usort

uasort($array, function ($a, $b) { 
    $a = $a['totalPreregistrations']; 
    $b = $b['totalPreregistrations']; 
    return ($a == $b) ? 0 : (($a < $b) ? -1 : 1); 
}); 


echo "<pre>"; 
print_r($array); 

輸出

Array 
(
    [element2] => Array <-------------------------- element key remains intact 
     (
      [Total] => 1 
      [paTotal] => 0 
      [totalPreregistrations] => 0 
      [totalPreregistrationsToDate] => 58 
      [pas] => Array 
       (
        [0] => Array 
         (
          [id] => 107 
         ) 

       ) 

     ) 

    [element1] => Array 
     (
      [Total] => 1 
      [paTotal] => 0 
      [totalPreregistrations] => 7 
      [totalPreregistrationsToDate] => 26 
      [pas] => Array 
       (
        [0] => Array 
         (
          [id] => 119 
         ) 

       ) 

     ) 

)