使用我在类的构造函数中创建的列表？

Question

为什么当我尝试运行 get_average() 方法时，它说我不能在 get_average() 方法中添加“int and grade”？我知道它可能必须这样做，因为它们是两种不同的类型，但我只是想知道如何解决它。

最后我的问题是我只是想知道如何修复我的代码，所以我可以将这个人的成绩添加到列表中，然后对它们进行平均或显示它们，我正在努力解决如何做到这一点。

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

    def add_grade(self, grade):
        if type(grade) == Grade:
            self.grades.append(grade)
            return self.grades

    def get_average(self):
        gradebook = self.grades
        total = 0
        for grade in gradebook:
            total += int(grade)
        avg = total / len(gradebook)
        return avg

    def get_name(self):
        return self.name

    def __repr__(self):
        return "{p} has these grades: {g}".format(p=self.name, g=self.grades)

# student1 = Student()
# student1.attendance = {
#   "11/1/98": True,
#   "11/2/98": False 
# }

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

    def is_passing(self):
        if self.score > self.minimum_passing:
            return "{p} is passing with a grade of {g}".format(p=pieter.get_name(), g=self.score)

# Checking for grades and averages
pieter.add_grade(Grade(100))
#print(pieter.get_average())
print(pieter)

# Tells you if the dude is passing
# roger_grade = Grade(100)
# print(roger_grade.is_passing())

Answer 1

在您的学生班级中，您有一个包含Grade 对象的成绩列表。 当您运行get_average() 时，它会尝试执行以下total += int(grade)。这失败了，因为您试图将对象强制转换为 int。

需要传入grade.score可以访问的等级的int值

同样，您需要更改def __repr__(self): 以打印出实际成绩，而不是成绩对象的地址。

这里是固定代码。

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

    def add_grade(self, grade):
        if type(grade) == Grade:
            self.grades.append(grade)
            return self.grades

    def get_average(self):
        gradebook = self.grades
        total = 0
        for grade in gradebook:
            total += int(grade.score)
        avg = total / len(gradebook)
        return avg

    def get_name(self):
        return self.name

    def __repr__(self):
        return "{p} has these grades: {g}".format(p=self.name, g=[sc.score for sc in self.grades])

# student1 = Student()
# student1.attendance = {
#   "11/1/98": True,
#   "11/2/98": False 
# }

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

    def is_passing(self):
        if self.score > self.minimum_passing:
            return "{p} is passing with a grade of {g}".format(p=pieter.get_name(), g=self.score)

# Checking for grades and averages
pieter.add_grade(Grade(100))
pieter.add_grade(Grade(0))


print(pieter.get_average())
print(pieter)

# Tells you if the dude is passing
# roger_grade = Grade(100)
# print(roger_grade.is_passing())