How can I make a multidimensional array with loop?

I'm working on a Laravel/Livewire project and there is a table with these Datas:

attribute, value, price

I need to make an array with this data with for loop that return something like this:

<pre lang="PHP">

$property=[
  'attribute1'=>['value'=>'price','value2'=>'price2','...'=>'...'],
  'attribute2'=>['value'=>'price','value2'=>'price2', '...'=>'...'],
  '...'=>['...'=>'...'],

];

$property= [
    'size'=>['x'=>'30000','xl'=>'35000'],
    'material'=>['wood'=>'55000','glass'=>'85000']
];

I try this but it returns wrong data



<pre lang="PHP">
public $product,$key,$properties;

public function mount($id){
    $this->product=Product::with('attr')->findOrFail($id);
  
    $db=DB::table('attr_product')->where('product_id',$id)->get()->unique('attr_id')->count();


    for ($I=0; $I<$dB;$I++) {
        $attr_id=$this->product->attr[$i]->id;
        $attr=$this->product->attr[$i]->title;
        $value=$this->product->attr[$i]->pivot->value;
        $price=$this->product->attr[$i]->pivot->price;
        $pivotTableCount=DB::table('attr_product')->where('attr_id',$attr_id)->count();
        for ($j=0;$j<$pivotTableCount;$j++){
           $vp=array($value=>$price);
        }


        $this->properties[]=[$attr=>$vp];

    }