course_id); $courses = collect(); foreach ($courses_id as $course_id) { $courses->push(\App\Course::find($course_id)); } return $courses; } public function saveCourses($courses) { $courses_id = []; foreach ($courses as $cours) { if ($cours != null){ array_push($courses_id,$cours->id); } } $this->course_id = implode(',',$courses_id); $this->save(); } }