Python属性在构造函数中设置值时不使用setter

Question

我有一个带有构造函数和几个属性的类

class Foo(object):
    def __init__(self, value1):
        self._value1 = value1

    @property
    def value1(self):
        return self._value1

    @property.setter
    def value1(self, value):
         assert value == 1
         self._value1 = value

现在，当我在创建对象时设置 value1 时，不使用 setter。我注意到了这一点，因为在输入错误值时没有调用断言。

如何让构造函数中设置的值使用setter？

Answer 1

您通过设置底层变量而不是使用属性来显式绕过 setter。去掉下划线。

def __init__(self, value1):
    self.value1 = value1

Answer 2

解决方案?

class Foo(object):
    def __init__(self, value1 = 0):
        self.value1 = value1    # Calling Set Property

    @property
    def value1(self):
        return self.__value1

    @property.setter
    def value1(self, value):
         assert value == 1
         self.__value1 = value

其他例子...

示例 1

class Product(object):
    
    def __init__(self, price = 0.0):
        self.price = price
    
    def get_price(self):
        return self.__price
    
    def set_price(self, value):
        if value < 0:
            raise ValueError("Price cannot be negative")
        self.__price = value
    
    price = property(get_price, set_price)

示例 2

class Product(object):

    def __init__(self, price = 0.0, name = ""):
        self.price = price
        self.name = name
    
    # property for __price attribute 
    @property
    def price(self):
        return self.__price

    @price.setter
    def price(self, value):
        if value < 0:
            raise ValueError("Price cannot be negative")
        self.__price = value

    # property for __name attribute 
    @property
    def name(self):
        return self.__name

    @name.setter
    def name(self, value):
        for ch in value:
            if ch.isdigit():
                raise Exception("Enter valid product name")
        self.__name = value

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