在PHP中，在给定原始顺序时，对已排序的对象数组进行分类的最佳方法是什么？

问题描述：

Let's say I have one array of ID numbers in a desired particular order. I have a second array of objects that were sorted by an ID property from the first array.

$array1 = [3,4,2,1,5];

$array2 = [
    ["id" => 1, "data" => "one"],
    ["id" => 2, "data" => "two"],
    ["id" => 3, "data" => "fre"],
    ["id" => 4, "data" => "foe"],
    ["id" => 5, "data" => "fie"]
];

In PHP, what is the best way of 'unsorting' or reverting the second array to the original order of the first array?

The closest answer I can find without using a sort is:

$array1_flipped = array_flip($array1);

$array2_unsorted = array();

for($i = 0; $i < count($array1); $i++) {
  $array2_unsorted[$array1_flipped[$array2[$i]['id']]] = $array2[$i];
}

return($array2_unsorted);

Edit: For those interested, here is how the question arose. The first array is a list of IDs to be displayed in a particular order. The second array is the return of the MySQL call WHERE id IN $array2, which is returned sorted. However, the second array needs to be resorted back into the order of the first array. Due to size issues, I was hoping to be able to remap the second array using the keys and values of the first array without sorting.

假设我有一个特定顺序的ID号数组。我有第二个对象数组，它们是由第一个数组的ID属性排序的。 p>

  $ array1 = [3,4,2,1,5]; 
  
 $ array2 = [
 [“id”=＆gt;  1，“data”=＆gt;  “one”]，
 [“id”=＆gt;  2，“数据”=＆gt;  “two”]，
 [“id”=＆gt;  3，“data”=＆gt;  “fre”]，
 [“id”=＆gt;  4，“数据”=＆gt;  “敌人”]，
 [“id”=＆gt;  5，“data”=＆gt;  “fie”] 
]; 
  code>  pre> 
 
 在PHP中，将第二个数组“解除”或恢复到第一个数组的原始顺序的最佳方法是什么？  ？ p> 
 
 
我能找到的最接近的答案是： p> 
 
 
  $ array1_flipped = array_flip（$ array1）; 
 \  n $ array2_unsorted = array（）; 
 
for（$ i = 0; $ i＆lt; count（$ array1）; $ i ++）{
 $ array2_unsorted [$ array1_flipped [$ array2 [$ i] ['id'  ]]] = $ array2 [$ i]; 
} 
 
return（$ array2_unsorted）; 
  code>  pre> 
 
  编辑 strong>：对于 那些感兴趣的人，这就是问题是如何产生的。 第一个数组是要按特定顺序显示的ID列表。 第二个数组是MySQL调用 WHERE id IN $ array2  code>的返回，返回排序。 但是，需要将第二个数组恢复到第一个数组的顺序。 由于大小问题，我希望能够使用第一个数组的键和值重新映射第二个数组而不用 em>排序。 p> 
  div>

答

I found the solution by introducing a third array and using a method similar to Gauss-Jordan elimination. While this is beautiful, I wish there was a one-step algorithm for this. I'll award the correct answer to anyone who finds it.

$array1 = [3,4,2,1,5];
$array2 = [
    ["id" => 1, "data" => "one"],
    ["id" => 2, "data" => "two"],
    ["id" => 3, "data" => "fre"],
    ["id" => 4, "data" => "foe"],
    ["id" => 5, "data" => "fie"]
];
// Placeholder sorted ascending array (e.g. $array3 = [1,2,3,4,5])
$array3 = range(1,count($array1));

array_multisort($array1, $array3);
// Now $array3 = [4,3,1,2,5], the inverse map of an $array1 sort

array_multisort($array3, $array2);

return $array2;

答

usort with an anonymous function receiving the order array via the use keyword:

$order = [3,4,2,1,5];

$ar = [
    ["id" => 1, "data" => "one"],
    ["id" => 2, "data" => "two"],
    ["id" => 3, "data" => "fre"],
    ["id" => 4, "data" => "foe"],
    ["id" => 5, "data" => "fie"]
];

usort($ar, function($a, $b) use ($order) {
    $ai = array_search($a['id'], $order);
    $bi = array_search($b['id'], $order);
    if($ai == $bi) return 0;
    return ($ai < $bi) ? -1 : 1;
});

print_r($ar);

在PHP中，在给定原始顺序时，对已排序的对象数组进行分类的最佳方法是什么？

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