public function cetak_guru(Request $request)
 {
     $type = $request->input('type');
     $guru = Guru::all();
     switch ($type) {
         case 'pdf':
             $data['guru'] = Guru::all();
             $pdf = PDF::loadView('admin.laporan.cetak_guru', $data)->setOrientation('landscape');
             return $pdf->stream();
             break;
         case 'excel':
             Excel::create('Data Guru', function ($excel) use($guru) {
                 //set properties
                 $excel->setTitle('Data Guru')->setCreator('Jamal Apriadi, S.Kom');
                 $excel->sheet('Laporan Nilai Siswa', function ($sheet) use($guru) {
                     $row = 1;
                     $sheet->row($row, array('No.', 'NIP', 'Nama', 'Mata Pelajaran'));
                     foreach ($guru as $s) {
                         $sheet->row(++$row, array($s->nip, $s->nama, $s->mapel->nm_mapel));
                     }
                 });
             })->export('xls');
             break;
         default:
             # code...
             break;
     }
 }
 /**
  * Display a listing of the resource.
  *
  * @return \Illuminate\Http\Response
  */
 public function index()
 {
     $guru = Guru::all();
     return View('admin.guru.index')->with('guru', $guru);
 }