多维索引数组到关联数组，具体取决于列值 [英] Multidimensional indexed array to associative array depending on column value

问题描述

我有一个多维索引数组.每个元素都是一个带有 id 列的关联数组，该列在元素之间是唯一的(其值永远不会在数组中重复).

I have a multidimensional indexed array. Each element is an associative array with an id column which is unique between elements (its value never repeats within the array).

[indexed] =>Array
(
    [0] => Array
        (
            [id] => john
            [name] => John
            [age] => 29
        ),

    [1] => Array
        (
            [id] => peter
            [name] => Peter
            [age] => 30
        ),

    [2] => Array
        (
            [id] => harry
            [name] => Harry
            [age] => 19
        )
)

我的目标是将该数组转换为多维关联数组，并由 id 值索引.

My goal is to convert this array into a multidimensional associative array, indexed by id values.

[indexed] =>Array
(
    [john] => Array
        (
            [id] => john
            [name] => John
            [age] => 29
        ),

    [peter] => Array
        (
            [id] => peter
            [name] => Peter
            [age] => 30
        ),

    [harry] => Array
        (
            [id] => harry
            [name] => Harry
            [age] => 19
        )
)

到目前为止，我最好的尝试是遍历数组元素并手动创建最终数组.

My best attempt so far is to loop over array elements and manually create the final array.

$associative = array();
foreach($indexed as $key=>$val) $associative[$val['id']] = $val;

我认为这不是最优雅的解决方案.内置的(更有效的)功能是否可以获得相同的结果?

I think it's not the most elegant solution. Is it possible to obtain the same result with built-in (more efficient) functions?

推荐答案

事实是 php确实提供了一个单一的本机函数，可让您用单个列的值替换外部索引.魔术"位于第二个参数中，该参数告诉php在分配新键时不要触摸子数组值.

The truth is php DOES offer a single, native function that allows you to replace the outer indexes with the values of a single column. The "magic" is in the 2nd parameter which tells php not to touch the subarray values when assigning the new keys.

代码:(演示)

$indexed = [
    ['id' => 'john', 'name' => 'John', 'age' => 29],
    ['id' => 'peter', 'name' => 'Peter', 'age' => 30],
    ['id' => 'harry', 'name' => 'Harry', 'age' => 19],
];

var_export(array_column($indexed, null, 'id'));

输出:

array (
  'john' => 
  array (
    'id' => 'john',
    'name' => 'John',
    'age' => 29,
  ),
  'peter' => 
  array (
    'id' => 'peter',
    'name' => 'Peter',
    'age' => 30,
  ),
  'harry' => 
  array (
    'id' => 'harry',
    'name' => 'Harry',
    'age' => 19,
  ),
)

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