class or object instead of dictionaries in Python 2

Question

I normally use nested dictionaries, but I'd like to move into classes and objects. I have a list of home work grades that look like:

assignment_name assignment_subject student_name due_date grade grade_pct rank

I'd like to make an object that holds all the students and each students holds all of their assignments details. My dictionary would look like:

homeworks['student_name']['assignment_name'] = {'assignment_subject': 'math', 'due_date': '11/12/13', 'grade': 15, 'grade_pct': 15/20.0, 'rank': 'B'}

Should this be a class within a class?

class Homeworks(object):
    def _init_(self):
        self.students

    class student(object):
        def _init_(self,student_name):
             self.student_name = student_name

        def add_assignment(line):
             student.assignment_name = line[0]
             student.assignment_subject = line[1]
             student.grade = line[4]

I know this isn't right. I don't know if I am on the right track or not. I do need to be able to access the grades for one student. (for assignment in Homeworks['Robbie Michaels'].keys(): print Homeworks['Robbie Michaels'][assignment]['grade']) I also like to access them using if assignment_subject == 'math' etc.

Your dictionary syntax is not valid Python; use `{key: value, key: value}` instead; a colon, not an equals sign. — Martijn Pieters, Nov 22 '13 at 17:11
`Student` shouldn't be a nested class, it should be its own class. — Henrik Andersson, Nov 22 '13 at 17:11

score 1 · Accepted Answer · edited May 23 '17 at 12:12

class student:
    def __init__(self, student_name):
        self.name = student_name

class homework:

    def __init__(self,student_name,assignment_name,assignment_subject,grade):
        self.student = student(student_name)
        self.assignment_name = assignment_name
        self.assignment_subject = assignment_subject
        self.grade = grade

    @classmethod
    def new_hw(cls, line):
        return cls(line[0],line[1],line[2],line[3])

    @classmethod
    def get_all_grades(cls, student_name, homework_list):
        return [ x.grade for x in homework_list if student_name is x.student.name]

lines = [["abc","a","b","A"],["abc","c","d","B"],["ebc","c","d","B"]]
hw_list = [homework.new_hw(line) for line in lines]
print homework.get_all_grades("abc",hw_list)

What you need to understand is "How to design Object-Orientedly?". The above code, may not be the best of designs, hence, try this to learn where to start. How do I design a class in Python?

Thank you! this makes so much more sense. I will work on the How to design piece. I appreciate the additional reference. — Climbs_lika_Spyder, Nov 22 '13 at 17:57
You should also try `@staticmethod`s and not just `@classmethod`s and see what function type fits what definition. — tmj, Nov 22 '13 at 19:47

score 0 · Answer 2 · answered Nov 22 '13 at 17:12

Don't do that.

Just make a Homework class and a Student class.

You can create a list of Homework classes and then just pass the students that are part of each "homework" to their respective object.

For example:

class Homework(object):
    def _init_(self, name, subject):
       self.assignment_name = name
       self.assignment_subject = name
       self.students = []

    def add_student(self, student):
       self.students.append(student)

class Student(object):
    def _init_(self, student_name):
         self.student_name = student_name

You can expand from there.

What I would really do is have a list of Classes that each have homework.

And each student could be in multiple Classes, etc, but it really all up to you

Have fun with it!

With this method can I somehow list all of the grades for one student at a time? I could with `for assignment in Homeworks['Robbie Michaels'].keys(): print Homeworks['Robbie Michaels'][assignment]['grade']` — Climbs_lika_Spyder, Nov 22 '13 at 17:21

class or object instead of dictionaries in Python 2

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