Python Classes Review - Further Practice Discussion

Since we are instantiating a Grade class within the argument of the add_grade() method, it doesn’t get assigned as a referable instance except by accessing the grades instance variable (the list of grades).

pieter.add_grade(Grade(100))
  def get_grades(self):
    return [x.score for x in self.grades]
grades = pieter.get_grades()
print (grades[0])    # 100
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It’s also nice to incorporate the minimum_passing attribute of Grade into the Student class, to check if a student will pass given their average:

  def will_pass(self):
    return self.get_average() >= Grade.minimum_passing

Anyway, I finally understand this lesson completely. Thanks for the support here on the forums everyone!

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4 posts were split to a new topic: Can’t make get_average to work

2 posts were split to a new topic: Why did this one need return?

A post was merged into an existing topic: How can I access Pieter’s grade after it has been added?

7 posts were split to a new topic: What do we actually need to do in the last additional “challenge”

2 posts were split to a new topic: To use datetime objects as the key value for the dictionary

6 posts were split to a new topic: Explain the meaning of type(grade)==Grade?

28 posts were split to a new topic: How do i print the results of self.grades using the repr method?

changing grade to grade.score worked for me.

print(grade) gives you <main.Grade object at 0x7feebe938b38> or something like that

print(grade.score) gives you a int

the int you can append to self.grades

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You’ll want to append Grade objects (instances of the Grade class) not just the score. If all we want to append is the score, there’d be no point in creating Grade objects.

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4 posts were split to a new topic: How did you make it a subclass?

3 posts were split to a new topic: Does the below work for the get average question?

5 posts were split to a new topic: What’s going wrong despite using “grade.score” to append “self.grades”

6 posts were split to a new topic: What is the mean of code if type(grade) == Grade

This is my first post here, so here goes…

I also fought with the solution to the average score section of this Review. I read all the posts here and came up with this solution. I’m still not feeling like I fully understand this lesson, but I am learning a lot, and I am happy to get this working!

Under “class Student:”

def get_average(self):
    #var. to hold scores as added
    temp = 0
    #var. to get length of how many scores are in grades
    avgl = len(self.grades)
    #var. to limit number of loops for while loop
    counter = 0
    while counter < avgl:
        #adds each score to the total. The counter var will advance and allow access to each list item.
        temp += self.grades[counter].score
        #advances count for loop
        counter += 1
    #calculate average of scores    
    avg = temp / avgl
    return avg

pieter.add_grade(Grade(100))
pieter.add_grade(Grade(80))
print(pieter.get_average())

90.0

If I missed the point of the exercise, any input is welcome please!

Given the amount of iterations is know, I would use a for loop.

As would I. Was just going to comment when I saw this.

We can further abstract away self by iterating over, self.grades.

for grade in self.grades:    # grade is a Grade object
     t += grade.score

sample code:

Output for the print statements is shown below :

print(roger)
print(sandro)
print(pieter)
print("=====================")
print(f"Was {roger.name} in attendance on '24 Jan 2020?' : {roger.get_attendance('01/22/2020')}")

ccClassesReview

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Hi, I am struggleling with an error who tells me it missing a postionnal argument “self”, on the condition “if Grade.is _passing():”
After some research, it looks like it is because I should create an instance of my class before to call a method. But my objects already exist (pieter = Student(“Pieter Bruegel the Elder”, 8) and pieter_grade = Grade([85, 77, 100]) ).
Someone to show me the way please?

class Student:
    def __init__(self, name, year):
        self.name = name
        self.year = year
        self.grades = []

    def __repr__(self):
        if Grade.is_passing():
            return "Student: " + str(self.name) +", " + str(self.year) + " years, grades is " + str(self.grades[0]) + ", student is passing"
        else:
            return "Student: " + str(self.name) +", " + str(self.year) + " years, grades is " + str(self.grades[0]) + ", student is not passing"


    def add_grade(self, grade):
        if isinstance(grade, Grade):
          self.grades.append(grade)


####################################################
roger = Student("Roger van der Weyden", 10)
sandro = Student("Sandro Botticelli", 12)
pieter = Student("Pieter Bruegel the Elder", 8)
###################################################


class Grade:
    minimum_passing = 65

    def __init__(self, score):
        self.score = score
        self.total = 0
        for num in score:
            self.total += num

    def __repr__(self):
        average = self.total / len(self.score)
        self.result = str(round(average, 2))
        return "Average score is: " + str(self.result)

    def is_passing(self):
        if float(self.result) >= float(self.minimum_passing):
            #return print("passing")  #return None in addition on the print, why?
            return True
        else:
            #return print("not passing") #return None in addition on the print, why?
            return False



####################################################
pieter_grade = Grade([85, 77, 100])
pieter.add_grade(pieter_grade)
print(pieter)
####################################################