Question

我有以下程序试图演示多级继承。不幸的是，在调用m2和eligible_for_reward方法时，我得到以下内容：

m2=Marks()
m2.eligible_for_reward()

错误：

Marks has no attribute totalmarks

代码如下：

# Define a class as 'student'
class Student:
    # Method
    def getStudent(self):
        self.name = input("Name: ")
        self.age = input("Age: ")
        self.gender = input("Gender: ")

#The Test Class inherits from the Student Class.
class Test(Student):
    # Method
    def getMarks(self):
        self.stuClass = input("YearGroup/Class: ")
        print("Enter the marks of the respective subjects")
        self.literature = int(input("Literature: "))
        self.math = int(input("Math: "))
        self.biology = int(input("Biology: "))
        self.physics = int(input("Physics: "))

# Note that the Marks Class inherits from the Test Class and in doing so inherits from the Student Class
class Marks(Test):    
    # Method
    def display(self):
        print("\n\nName: ",self.name)
        print("Age: ",self.age)
        print("Gender: ",self.gender)
        print("Class Year Group: ",self.stuClass)
        self.totalmarks=self.literature+self.math+self.biology+self.physics
        print("Total Marks: ", self.literature + self.math + self.biology + self.physics)

    def eligible_for_reward(self):
        if self.totalmarks>=90 and self.age>13:
            print("You are eligible for the fabulous school sponsored trip to London")
        else:
            print("Sorry, you are not eligible and so are going nowhere....!")

更新：

我也尝试过以下方法，即相关方法中的definig self.totalmarks，但也出现了错误：名称'totalmarks'未定义

def eligible_for_reward(self):
        self.totalmarks=totalmarks
        if self.totalmarks>=90 and self.age>13:
            print("You are eligible for the fabulous school sponsored trip to London")
        else:
            print("Sorry, you are not eligible and so are going nowhere....!")

此外，我也尝试了

    m2=Marks()
    m2.display()
    m2.eligible_for_reward()

和错误：

AttributeError: 'Marks' object has no attribute 'name'

Answer 1

您可以在self.totalmarks类

的display()方法中定义属性Marks

因此，当您调用qualified_for_reward（）时，此时不会定义总标记。所以你可以先调用display（）方法来解决这个问题：

m2=Marks()
m2.dispay()
m2.eligible_for_reward()

但这不会起作用，因为目前还没有定义self.literature self.math self.biology self.physics。

您必须将 init （）方法添加到所有类中以调用super（）并正确实例化该类，如下所示：

class Student:
    def __init__(self):
        self.name = input("Name: ")
        self.age = input("Age: ")
        self.gender = input("Gender: ")

class Test(Student):
    def __init__(self):
        super(Test, self).__init__()
        self.stuClass = input("YearGroup/Class: ")
        print("Enter the marks of the respective subjects")
        self.literature = int(input("Literature: "))
        self.math = int(input("Math: "))
        self.biology = int(input("Biology: "))
        self.physics = int(input("Physics: "))

class Marks(Test):    
    def __init__(self):
        super(Marks, self).__init__()
        self.total_marks = self.literature + self.math + self.biology + self.physics

    def display(self):
        print("\n\nName: ",self.name)
        print("Age: ",self.age)
        print("Gender: ",self.gender)
        print("Class Year Group: ",self.stuClass)

        print("Total Marks: ", self.literature + self.math + self.biology + self.physics)

    def eligible_for_reward(self):
        if self.total_marks>=90 and self.age>13:
            print("You are eligible for the fabulous school sponsored trip to London")
        else:
            print("Sorry, you are not eligible and so are going nowhere....!")

你可以按照以下方式使用它：

marks = Marks()
marks.eligible_for_reward()
marks.display()

Answer 2

正如我在评论中提到的，我没有看到你进行子类化的原因。所以我把它作为一个班级学生放在一起这样：

class Student:
    # Method
    def __init__(self):
        self.name = input("Name: ")
        self.age = int(input("Age: "))
        self.gender = input("Gender: ")

    def setMarks(self):
         self.stuClass = input("YearGroup/Class: ")
         print("Enter the marks of the respective subjects")
         self.literature = int(input("Literature: "))
         self.math = int(input("Math: "))
         self.biology = int(input("Biology: "))
         self.physics = int(input("Physics: "))
         self.totalmarks=self.literature+self.math+self.biology+self.physics

    def display(self):
         print("\n\nName: ",self.name)
         print("Age: ",self.age)
         print("Gender: ",self.gender)
         print("Class Year Group: ",self.stuClass)
         self.totalmarks=self.literature+self.math+self.biology+self.physics
         print("Total Marks: ", self.literature + self.math + self.biology + self.physics)

    def eligible_for_reward(self):
         if self.totalmarks>=90 and self.age>13:
             print("You are eligible for the fabulous school sponsored trip to London")
         else:
             print("Sorry, you are not eligible and so are going nowhere....!")

使用示例：

s1 = Student()
>>> Name: Hans
>>> Age: 17
>>> Gender: m
s1.setMarks()
>>> YearGroup/Class: 2017
>>> Enter the marks of the respective subjects
>>> Literature: 11
>>> Math: 14
>>> Biology: 42
>>> Physics: 10

s1.display()


>>> Name:  Hans
>>> Age:  17
>>> Gender:  m
>>> Class Year Group:  2017
>>> Total Marks:  77

s1.eligible_for_reward()
>>> Sorry, you are not eligible and so are going nowhere....!

Answer 3

这是使用最少编辑的工作代码，希望这可以帮助您： -

class Student:
    # Method
    def getStudent(self):
        self.name = input("Name: ")
        self.age = int(input("Age: "))
        self.gender = input("Gender: ")

#The Test Class inherits from the Student Class.
class Test(Student):
    def __init__(self):
        super().__init__()
        super().getStudent()
    # Method
    def getMarks(self):
        self.stuClass = input("YearGroup/Class: ")
        print("Enter the marks of the respective subjects")
        self.literature = int(input("Literature: "))
        self.math = int(input("Math: "))
        self.biology = int(input("Biology: "))
        self.physics = int(input("Physics: "))

# Note that the Marks Class inherits from the Test Class and in doing so inherits from the Student Class
class Marks(Test):
    def __init__(self):
        super().__init__()
        super().getMarks()
    # Method
    def display(self):
        print("\n\nName: ",self.name)
        print("Age: ",self.age)
        print("Gender: ",self.gender)
        print("Class Year Group: ",self.stuClass)
        self.totalmarks=self.literature+self.math+self.biology+self.physics
        print("Total Marks: ", self.literature + self.math + self.biology + self.physics)

    def eligible_for_reward(self):
        if self.totalmarks>=90 and self.age>13:
            print("You are eligible for the fabulous school sponsored trip to London")
        else:
            print("Sorry, you are not eligible and so are going nowhere....!")



mrk = Marks()
mrk.display()
mrk.eligible_for_reward()

属性创建和引用Python类多级继承时出错

3 个答案: