显示具有多对多关系laravel 5.4的字段

I'm the beginner of laravel 5.4. I just want to ask. I want to display in Assignments table the Collectors but it doesn't show.

Screenshot of the Assignments Index

Code in my Assignment index.blade.php

<td>{{ $assignment->collector['firstname'] }} {{ $assignment->collector['lastname'] }}</td> 

Assignment.php model

public function collectors()
{
    return $this->belongsToMany(Collector::class);
}

Collector.php model

public function assignments()
{
    return $this->belongsToMany(Assignment::class);
}

AssignmentsController

public function index()
{
    $assignments = Assignment::all();

    return view('assignments.index', compact('assignments'));
}

I search to how to display the collectors with both many to many relationship. I read the doc about using pivot but I had still errors about that. Can you help me resolving this? Thanks

$collector is an object, not an array. Use -> syntax to access properties on individual collector models:

$collector->firstname

Since the relationship is many to many you need two loops:

@foreach($assignments as $assignment)
     @foreach($assignment->collectors as $collector)
        <td>{{ $collector->firstname }} {{ $collector->lastname }}</td>
    @endforeach
@endforeach

If you find you often need two fields together, like first and last names, you can create an accessor on the Collector model to easily join them:

public function getFullNameAttribute()
{
    return $this->getAttribute('firstname') . ' ' . $this->getAttribute('lastname');
}

Allowing you to then do:

@foreach($assignments as $assignment)
     @foreach($assignment->collectors as $collector)
        <td>{{ $collector->fullname }}</td>
    @endforeach
@endforeach