Object of class Illuminate\Support\Collection could not be converted to int -laravel

Question

When i run my project, i get the error

Object of class Illuminate\Support\Collection could not be converted to int

pointing to the code line

$classes =['0'=>'All']+ClassModel::pluck('name','code');

How can i get this solved?

PS: Laravel Beginner

Controller

public function show()
    {
        $selectedClass = Input::get('class',0);
        $classes =['0'=>'All']+ClassModel::pluck('name','code');
        if($selectedClass){
            $Subjects=  DB::table('Subject')
                ->join('Class', 'Subject.class', '=', 'Class.code')
                ->select('Subject.id', 'Subject.code','Subject.name','Subject.type', 'Subject.subgroup','Subject.stdgroup','Subject.totalfull',
                    'Subject.totalpass','Subject.gradeSystem','Subject.wfull', 'Subject.wpass','Subject.mfull','Subject.mpass','Class.Name as class','Subject.sfull','Subject.spass',
                    'Subject.pfull','Subject.ppass')
                ->where('Subject.class',$selectedClass)
                ->get();
        }
        else{
            $Subjects=  DB::table('Subject')
                ->join('Class', 'Subject.class', '=', 'Class.code')
                ->select('Subject.id', 'Subject.code','Subject.name','Subject.type', 'Subject.subgroup','Subject.stdgroup','Subject.totalfull',
                    'Subject.totalpass','Subject.gradeSystem','Subject.wfull', 'Subject.wpass','Subject.mfull','Subject.mpass','Class.Name as class','Subject.sfull','Subject.spass',
                    'Subject.pfull','Subject.ppass')
                ->get();
        }
        return View::Make('app.subjectList',compact('Subjects','classes','selectedClass'));
    }

Answer 1

You have to convert the collection into an array:

$classes = ['0'=>'All'] + ClassModel::pluck('name','code')->all();