如何在 Python3 中将参数传递给具有相同对象的内部 class 外部和内部 classes？

Question

下面的代码在我为外部和内部类分别创建对象并传递参数的情况下运行良好

class Student:
    def __init__(self,name,rollno):
        self.name = name
        self.rollno = rollno
    def show(self):
        print(self.name,self.rollno)
        #self.lap.show()

    class Laptop: #inner class
        def __init__(self,brand,cpu'):
            self.brand = brand
            self.cpu = cpu
        def show(self):
            print(self.brand,self.cpu)
s1 = Student('Ram',21)
lap1 =s1.Laptop('Dell','i3')
lap1.show()

In the second code, I have created the inner class(Laptop) object inside the Outer(Student) class. In that case, how can we pass the arguments to the inner class?

class Student:
    def __init__(self,name,rollno):
        self.name = name
        self.rollno = rollno
        self.lap = self.Laptop()  #lap is the obj of a inner class

    def show(self):
        print(self.name,self.rollno)
        self.lap.show()

I tried with self.lap = self.Laptop(brand,cpu), assigning parameters and passing the arguments in differnet ways, but none worked for me. Is there any way where I can pass the arguments?

Answer 1

我真的看不到内部 class 的额外好处。我见过很少的用例，它们实际上有助于提高代码的可读性。在您的代码中，我建议只使用两个 'top level' classes。只有在一些复杂的情况下，内部 classes 才真正有用。

class Student:
    def __init__(self, name, rollno, laptop=None):
        self.name = name
        self.rollno = rollno
        self.laptop = laptop

    def show(self):
        print(self.name, self.rollno)
        if self.laptop:
            self.laptop.show()

class Laptop:
    def __init__(self, brand, cpu):
        self.brand = brand
        self.cpu = cpu

    def show(self):
        print(self.brand, self.cpu)

然后在使用中，只需初始化并根据需要传递它们：

lap1 = Laptop('Dell', 'i3')
s1 = Student('Ram', 21, lap1)
lap1.show()
s1.show()
s2 = Student('Whosebug', 9999, lap1)
s2.show()
s3 = Student('No laptop', 2)
s3.show()

Answer 2

如果您真的希望 Laptop class 包含在 Student class 中，要么将参数传递给 Student 构造函数，要么将 self.lap = self.Laptop() 替换为self.lap = None。这样你就不需要在创建学生时担心这些参数，以后可以像第一个例子一样将笔记本电脑分配给学生。

class Student:
    def __init__(self,name,rollno):
        self.name = name
        self.rollno = rollno
        self.lap = None  #lap is the obj of a inner class

    def show(self):
        print(self.name,self.rollno)
        self.lap.show() 

    class Laptop: #inner class
        def __init__(self,brand,cpu):
            self.brand = brand
            self.cpu = cpu
        def show(self):
            print(self.brand,self.cpu)

s1 = Student('Ram',21)
lap1 =s1.Laptop('Dell','i3')
lap1.show()

如何在 Python3 中将参数传递给具有相同对象的内部 class 外部和内部 classes？

How to pass arguments to inner class with same object for Outer and Inner classes in Python3?

python

oop

class

inner-classes

python-3.x