# 修改與刪除@property封裝的數據屬性

# 原始通過@property實現的功能：將類中定義的函數屬性，通過裝飾器@property將其封閉成數據屬性，這時是不能刪除和修改這個數據屬性的

class Room:
    def __init__(self, name, width, length):
        self.name = name
        self.width = width
        self.length = length

    @property
    def area(self):
        return self.width * self.length


r1 
 
= Room(‘廚房‘, 10, 4)
print(r1.area)


r1.area = 100  # AttributeError: can‘t set attribute
del r1.area  # AttributeError: can‘t delete attribute


# @property補充，可以修改和刪除封裝後的屬性
class Goods:
    def __init__(self):
        self.original_price = 100  # 原價
        self.discount = 0.8  # 折扣

    @property  # 這個必須放在setter和deleter的前面，否則不能修改下面的兩種方法
 

    def price(self):
        new_price = self.original_price * self.discount  # 實際價格=原價*折扣
        return new_price

    @price.setter
    def price(self, value):
        self.original_price = value

    @price.deleter
    def price(self):
        del self.original_price


obj = Goods()
print(obj.price)  #
 
 獲取價格
obj.price = 200  # 修改原價
print(obj.price)
del obj.price  # 刪除原價


# 以上的寫法也可以這樣寫

class Goods:
    def __init__(self):
        self.original_price = 100  # 原價
        self.discount = 0.8  # 折扣

    def get_price(self):
        new_price = self.original_price * self.discount  # 實際價格=原價*折扣
        return new_price

    def set_price(self, value):
        self.original_price = value

    def del_price(self):
        del self.original_price

    price = property(get_price, set_price, del_price)  # 順序必須為get、set、del


obj = Goods()
print(obj.price)  # 獲取價格
obj.price = 200  # 修改原價
print(obj.price)
del obj.price  # 刪除原價



# 用@property實現的數據類型檢測
class People:
    def __init__(self, name):
        self.name = name  # 實例化就觸發property

    @property
    def name(self):
        # return self.name #無限遞歸
        return self.newname

    @name.setter
    def name(self, value):
        if not isinstance(value, str):
            raise TypeError(‘名字必須為字符串‘)
        self.newname = value

    @name.deleter
    def name(self):
        del self.newname


p1 = People(‘張三‘)  # self.name實際是存放到self.newname中
p1.name = 1  # 這裏就會報錯

修改與刪除@property封裝的數據屬性