在此 python 代码中出现属性错误

Question

Hello every one, when I run this code, I get a attribute error. I used two diffrent ways to find the area of pyramid but the second way is not working. I do not know how to solve this problem. If you know how to solve this problem, please help me. thanks a lot!

    class Rectangle:
        def __init__(self, length, width) -> None:
            self.length = length
            self.width = width

        def area(self) -> float:
            return self.length * self.width
    
        def perimeter(self) -> float:
            return 2 * self.length + 2 * self.width

        class Square(Rectangle):
            def __init__(self, length) -> None:
                super(Square, self).__init__(length, length)

        class Cube(Square):
            def surface_area(self) -> float:
                face_area = super(Square, self).area()
                return face_area * 6

            def volume(self) -> float:
                face_area = super(Square, self).area()
                return face_area * self.length

        class Triangle:
            def __init__(self, base, height) -> None:
                self.base = base
                self.height = height

            def tri_area(self) -> float:
                return 0.5 * self.base * self.height

        class RightPyramid(Square, Triangle):
            def __init__(self, base, slant_height) -> None:
                self.base = base
                self.slant_height = slant_height
                super().__init__(self.base)

            def area(self) -> float:
                base_area = super(Square, self).area()
                perimeter = super(Square, self).perimeter()
                return 0.5 * perimeter * self.slant_height + base_area

            def area_2(self) -> float:
                base_area = super(Square, self).area
                triangle_area = super(Triangle, self).tri_area()
                return triangle_area * 4 + base_area

        print(RightPyramid.__mro__) 
        pyramid = RightPyramid(3, 6)
        print(pyramid.area())
        print(pyramid.area_2())

Answer 1

I notice you are using inheritance all the way through your classes.

While I agree a Square is a subclass of Rectangle, a Cube in not a subclass of Squares, it is composed of Squares (hint, read up about composition vs inheritance).

Also since python 3, super() does not need arguments in most cases.

There are a couple of problems in your code:

• RightPyramid.__init__ does one super().__init__(self.base) , so how should super(Triangle, self).tri_area() access the height ?
• In area_2 , you're accessing super(Square, self).area , not actually calling it.

This is what I can offer you for your RightPyramid problem.

class Rectangle:
    def __init__(self, length, width) -> None:
        self.length = length
        self.width = width

    def area(self) -> float:
        return self.length * self.width

    def perimeter(self) -> float:
        return 2 * self.length + 2 * self.width


class Square(Rectangle):
    def __init__(self, length) -> None:
        super(Square, self).__init__(length, length)


class Triangle:
    def __init__(self, base, height) -> None:
        self.base = base
        self.height = height

    def tri_area(self) -> float:
        return 0.5 * self.base * self.height


class RightPyramid:
    def __init__(self, base, slant_height) -> None:
        self.base = Square(base)
        self.side = Triangle(base, slant_height)

    def area(self) -> float:
        base_area = self.base.area()
        perimeter = self.base.perimeter()
        return 0.5 * perimeter * self.side.height + base_area

    def area_2(self) -> float:
        base_area = self.base.area()
        triangle_area = self.side.tri_area()
        return triangle_area * 4 + base_area