如何从一维数组创建具有关联子数组的数组？

Question

I have the following array.

Array(
[1041] => 30
[1046] => 10
[1047] => 10
)

and I want to store it like following.

Array([0] => Array
(
    [material_name] => 1041
    [material_qty] => 30
) 
[1] => Array
(
    [material_name] => 1046
    [material_qty] => 10
)
[2] => Array
(
    [material_name] => 1047
    [material_qty] => 10
) )

now i am trying to store key values but it stores only last one.

for($i=0; $i<count($materials); $i++){
              foreach($materials as $key => $value){
                 $dataArrMaterial[$i] = array(
                        'material_name' => $key,
              'material_qty' => $value
                         );
              } }
              _print($dataArrMaterial);

my output is follwoing.

Array(
[0] => Array
    (
        [material_name] => 1047
        [material_qty] => 10
    )

[1] => Array
    (
        [material_name] => 1047
        [material_qty] => 10
    )

[2] => Array
    (
        [material_name] => 1047
        [material_qty] => 10
    ) )

now please help me do to that. thanks in advance.

Answer 1

You can simplify this quite a lot:

<?php
// ...
$dataArrMaterial = [];
foreach ($materials as $materialName => $materialQty) {
    $dataArrMaterial[] = [
        "material_name" => $materialName ,
        "material_qty" => $materialQty
    ];
}

Answer 2

Since it wasn't explained to you why , I will.

for($i=0; $i<count($materials); $i++){
    foreach($materials as $key => $value){
        // the value of $i is not changed within this loop
        $dataArrMaterial[$i] = array('material_name' => $key, 'material_qty' => $value);
    }
    // when the for() loop starts again, $i is incremented
}

So, on the first iteration of the foreach loop, you are assigning all subarrays to the same $i key ( 0 ). After 1041 is looped, your output array looks like this:

[0 => ["material_name" => 1041, "material_qty" => 30]];

After 1046 , the first pushed subarray is overwritten because keys on the same level must be unique.

[0 => ["material_name" => 1046, "material_qty" => 10]];

Then the third element overwrites the second in the output array:

[0 => ["material_name" => 1047, "material_qty" => 10]];

Once the inner loop ( foreach ) is finished, the outer loop ( for ) increments $i and the "overwriting" process repeats for the 1 key of the output array. And then again because count($materials) = 3 (three iterations).

This is why you are getting the final set of values repeated like this:

[0 => ["material_name" => 1047, "material_qty" => 10]];
[1 => ["material_name" => 1047, "material_qty" => 10]];
[2 => ["material_name" => 1047, "material_qty" => 10]];

As for the best way to perform this task, you can use a solution from my duplicate link or do it as Arkascha has demonstrated.