如何使用多重继承不混淆 class 变量？

Question

我需要创建一个 'Balance' class，这将是两个 parent classes 'Income' 和 'Expenses' 的儿子。 'Income' 和 'Expenses' 应该是容器，我将在其中放置一些数字，稍后找出 'Income' 的总和与 'Expenses' 的总和之间的差异。

from dataclasses import dataclass


@dataclass
class Income:

    first_Income: int = 0
    second_Income: int = 0
    third_Income: int = 0

    def all_vars_Income(self):
        return [attr for attr in dir(self) if not callable(getattr(self, attr)) and not attr.startswith('__')]

    def sum_Income(self):
        return sum([getattr(self, var) for var in self.all_vars_Income()])


@dataclass
class Expenses:

    first_Expenses: int = 0
    second_Expenses: int = 0
    third_Expenses: int = 0

    def all_vars_Expenses(self):
        return [attr for attr in dir(self) if not callable(getattr(self, attr)) and not attr.startswith('__')]

    def sum_Expenses(self):
        return sum([getattr(self, var) for var in self.all_vars_Expenses()])


class Balance(Income, Expenses):
    def sum_Balance(self):
        return Income.sum_Income(self) - Expenses.sum_Expenses(self)


user = Balance()
print(Balance.all_vars_Income(user))
# ['first_Expenses', 'first_Income', 'second_Expenses', 'second_Income', 'third_Expenses', 'third_Income']
print(Income.all_vars_Income(user))
# ['first_Expenses', 'first_Income', 'second_Expenses', 'second_Income', 'third_Expenses', 'third_Income']
print(Income.all_vars_Income(Income))
# ['first_Income', 'second_Income', 'third_Income']
user.__setattr__('first_Income', 50)
user.__setattr__('second_Expenses', 100)
print(Income.sum_Income(user))
# 150
print(user.sum_Balance())
# 0

因此，如您所见，问题是第一个 class 的变量和第二个 class 的变量有点混淆。我想将变量保持在适当的 classes 范围内，并且只使用这些变量的总和来计算差异。当我在这一行 "user.__setattr__('first_Income', 50)" 时，我只想更改收入 class 的值，这样我就可以将支出 class 的所有变量的总和保持为 0。可能，它是混乱的，但我希望你明白这一点。

Answer 1

我建议用这种方式来构建你的代码，它不仅解决了你的主要问题，而且符合 python 的风格指南，更好地利用了类的能力和功能（尽管为简单起见，我省略了异常处理）：

from dataclasses import dataclass, field


@dataclass
class Income:
    incomes: list[int] = field(default_factory=list)

    def sum_incomes(self):
        return sum(self.incomes)

    def add_income(self, income):
        self.incomes.append(income)

    def modify_income(self, number, income):
        self.incomes[number] = income


@dataclass
class Expenses:
    expenses: list[int] = field(default_factory=list)

    def sum_expenses(self):
        return sum(self.expenses)

    def add_expense(self, expense):
        self.expenses.append(expense)

    def modify_expense(self, number, expense):
        self.expenses[number] = expense


@dataclass
class Balance(Income, Expenses):
    def sum_balance(self):
        return self.sum_incomes() - self.sum_expenses()


user = Balance()
user.add_income(50)
user.add_expense(100)
print(user.sum_incomes())
# 50
print(user.sum_balance())
# -50
user.modify_income(0, 200)
print(user.sum_balance())
# 100

如何使用多重继承不混淆 class 变量？

How to not mix up class variables using multiple inheritance?

python

multiple-inheritance