我該如何處理這個錯誤：未定義的偏移量：0

Question

我正在制作一個在線學校平台，部分學生可以看到它的課程及其信息..但相關函數返回此錯誤：未定義偏移：0（視圖：C:\\xampp\\htdocs\\OnlineSchool\\resources\\views \\admin\\student\\ClassReport.blade.php)

模型之間有一些關系我的模型：

USER（學生和教師）Ì LEVEL（班級）Ì課堂。

=> 學生和課堂之間存在多對多關系（數據透視表）

請讓我遠離這個愚蠢的錯誤用戶：

    class User extends Authenticatable
{
    use Notifiable;

    /**
     * The attributes that are mass assignable.
     *
     * @var array
     */
    protected $fillable = [
        'name', 'email', 'password','image','level','code_meli',
    ];

    /**
     * The attributes that should be hidden for arrays.
     *
     * @var array
     */
    protected $hidden = [
        'password', 'remember_token',
    ];

    /**
     * The attributes that should be cast to native types.
     *
     * @var array
     */
    protected $casts = [
        'email_verified_at' => 'datetime',
    ];

   public function classroom(){
        return $this->hasMany  (classroom::class);
    }

    public function ClassRoomStudent(){
        return $this->belongsToMany (classroom::class ,'classroom_user','user_id','classroom_id');
    }
}

課堂：

class classroom extends Model
{
    protected $fillable = [
        'title', 'teacher_id', 'level_id','day','time','price',
    ];

    public function Student(){
        return $this->belongsToMany (user::class ,'classroom_user','classroom_id','user_id');
    }

    public function level(){
        return $this->belongsTo (level::class );
    }
    public function teacher(){
        return $this->belongsTo (user::class );
    }

}

等級 ：

class level extends Model
{
    protected $fillable = [
        'title',
    ];

    public function classroom(){
        return $this->hasMany (classroom::class);
    }
    public function exam(){
        return $this->hasMany (exam::class);
    }
}

和我在控制器中的功能：

public function MyClasses(){
    $student_id=auth ()->user ()->id;
    $classrooms=classroom::with ('level','teacher','factor')->wherehas('student',function ($q) use($student_id){
        $q->where('id',$student_id);
    })->get();
     
    return view ('admin.student.ClassReport',compact ('classrooms','student_id'));
}

最后..我的刀片：

 @foreach($classrooms as $class)
                    <tr>

                        <td>{{$i++}}</td>
                        <td>{{$class->title}}</td>
                        <td>{{$class->teacher[0]->name}}</td>
                        .
                        .
                        .
                        .
                    </tr>
            @endforeach 

Answer 1

Classroom 只屬於一位老師，不需要使用 de 零索引，只需輸入 $class->teacher->name