How to get sum of weight as total_weight from one table and store it in another table

I had two similar fields namely total_weight that is in my phyto table and weight that is in my phyto_species table shown below

CreatePhytosTable

public function up()
{
    Schema::create('phytos', function (Blueprint $table) {
        $table->id();
        $table->string('customer_name');
        $table->string('phyto_number');
        $table->decimal('total_weight');
        $table->date('date_send');
        $table->softdeletes();
        $table->timestamps();
    });
}

CreatePhytoSpeciesTable

public function up()
{
    Schema::create('phyto_species', function (Blueprint $table) {
        $table->id();
        $table->integer('phyto_id')->unsigned();
        $table->integer('species_id')->unsigned();
        $table->integer('destination_id')->unsigned();
        $table->integer('preservation_id')->unsigned();
        $table->double('weight', 8,2);
        $table->softdeletes();
        $table->timestamps();
    });
}

I have been trying to sum weight using array_sum() as total weight and then assign it to ‘total_weight’ => $totalweight] shown below however when I save the error says Undefined variable: totalweight. I would like to request for assistance please

 public function store(CreatePhytoRequest $request)
     {
    
         $phyto = $this->phytoRepository->create(
            ['customer_name' => $request->customer_name,
            'phyto_number' => $request->phyto_number,
            'date_send' => $request->date_send,
            'total_weight' =>  $totalweight]
    
    );

         $species = $request->input('species_id', []);
         $weight = $request->input('weight', []);
         $destination = $request->input('destination_id', []);
         $preservation = $request->input('preservation_id', []);
    

  
         for ($i=0; $i < count($species); $i++) {
             if ($species[$i] != '') {
                 $phyto->species()->attach($species[$i], ['weight' => $weight[$i],'destination_id' => $destination[$i],'preservation_id' => $preservation[$i]]);
        }
        
    }
         //array_sum work fine
          $totalweight = array_sum($weight);
    

         Flash::success('Phyto saved successfully.');
 

   

         return redirect(route('consignment.phytos.index'));
}

Answer

declare the variable

$totalweight = array_sum($weight);

before you call it. Your code should be something like:

public function store(CreatePhytoRequest $request) {
         //Get everything from requests
         $weight = $request->input('weight', []);
         ...

         // Declare needed variables
         $totalweight = array_sum($weight);


         $phyto = $this->phytoRepository->create(
            ['customer_name' => $request->customer_name,
            'phyto_number' => $request->phyto_number,
            'date_send' => $request->date_send,
            'total_weight' =>  $totalweight]);

         ... // and so one
}