如何在Python中调用类内部的类方法？

Question

当我在 init 中调用类方法（在其中初始化对象）时，每次都会调用类方法 count_genre ，从而递增之前的值。我只想调用该方法一次。

class Furniture:

    materials = []
    material_count = {}

    def __init__(self, name, material):
        self.name = name
        self.material = material
        Furniture.materials.append(self.material)
        Furniture.count_material()

    @classmethod
    def count_material(cls):
        for material in cls.materials:
            cls.material_count[material] = cls.material_count.get(material, 0) + 1

Furniture("Chair", "Wood")
Furniture("Cushion", "Cotton")
Furniture("Table", "Glass")

print(Furniture.material_count)

这是我在终端上得到的信息： {“椅子”：3，“垫子”：2，“桌子”：1}

这就是我想要得到的： {“椅子”：1，“垫子”：1，“桌子”：1}

Answer 1

使用

Furniture

为一件家具建模。使用单独的类来对一组特定家具的信息进行建模。

import dataclass
import collections


@dataclasses.dataclass
class Furniture:
    name: str
    material: str



class FurnitureCollection:
     def __init__(self):
         self.material_count = collections.Counter()
         self.pieces = []

     def add(self, f: Furniture):
         self.pieces.append(f)
         self.material_count[f.material] += 1

     @property
     def materials(self):
         return list(self.material_count)


fc = FurnitureCollection()

fc.add(Furniture("Char", "Wood"))
fc.add(Furniture("Cushion", "Cotton"))
fc.add(Furniture("Table", "Glass"))


assert fc.material_count["Wood"] == 1
assert all(x in fc.materials for x in ["Wood", "Cotton", "Glass"])