I want to display all roles who user don't have.

I want to display all roles who user don't have. With that i display all roles who user have , i try with != but don't work he don't display in dropdown only if user has 1 role. else if user have much roles they dublicate in dropdown this don't work.

@foreach($user->modelHasRoles as $user->modelHasRole)
     @foreach($roles as $role)
                @if($user->modelHasRole->role_id == $role->id)
                        <option value="{{$role->id}}">{{$role->name}}</option>
                @else
                @endif
     @endforeach
@endforeach