"""__dict__屬性：查看對象內(nèi)部所有屬性名和屬性值組成的字典
在Python類的內(nèi)部，無論是類屬性還是實例屬性，都是以字典的形式進行存儲的，其中屬性名作為鍵，而值作為該鍵對應(yīng)的值。
"""
# 定義類
class Rect:
    # 定義屬性
    def __init__(self, length=0, width=0):
        self.length = length
        self.width = width
        self.area = length * width
    # 定義方法
    def area(self):
        self.area = self.width * self.length
        return self.area
# 創(chuàng)建一個長為4寬為5的矩形對象，計算面積
r1 = Rect(4, 5)
print(r1.area)  # 20
# 直接修改矩形面積屬性值
r1.area = 100
print(r1.__dict__)  # {'length': 4, 'width': 5, 'area': 100}
# 修改矩形寬度以達(dá)到修改矩形面積的效果, 失敗
r1.width = 111111
print(r1.area)  # 100
print(r1.__dict__)  # {'length': 4, 'width': 111111, 'area': 100}
# 修改矩形長度以達(dá)到修改矩形面積的效果，失敗
r1.length = 9999999
print(r1.area)  # 100
print(r1.__dict__)  # {'length': 9999999, 'width': 10, 'area': 100}
print(Rect.__dict__)
print(r1.__dict__)

# 注意：這里的getter、setter、deleter所修飾的函數(shù)名（func_area）的命名并不符合規(guī)范
# 只是為了更好的理解 “將函數(shù)轉(zhuǎn)化為具有相同名稱的屬性” 這句話
# 正確的規(guī)范應(yīng)該是 不帶_ 的屬性名
class Rect:
    def __init__(self, length=0, width=0):
        self.length = length
        self.width = width
        self._area = length * width  # 為了規(guī)范需要設(shè)置成保護成員屬性
    # 定義getter對應(yīng)的函數(shù)
    @property  # 需要@property裝飾器
    def func_area(self):
        print("重新計算面積并賦值")
        self._area = self.width * self.length
        return self._area  # @property修飾的函數(shù)需要一個返回值
    # @func_area.setter  # 需要 @函數(shù)名.setter 的裝飾器
    # def func_area(self, value):
    #     raise ValueError
    @func_area.setter  # 需要 @函數(shù)名.setter 的裝飾器
    def func_area(self, value):
        self._area = value
    @func_area.deleter
    def func_area(self):
        del self._area
r1 = Rect(4, 5)
print(r1.func_area)  # 20
r1.width = 10
print(r1.func_area)  # 40
r1.length = 20
print(r1.func_area)  # 200
r1.func_area = 80
print(r1.__dict__)  # {'length': 20, 'width': 10, '_area': 80}
del r1.func_area  # 將調(diào)用 deleter
print(r1.__dict__)  # {'length': 20, 'width': 10}
print(r1.func_area)  # 200
print(r1.__dict__)  # {'length': 20, 'width': 10, '_area': 200}
# r1.func_area = 80  # 報錯：ValueError

class C:
    def __init__(self):
        self._x = "zhangsan"
    @property
    def x(self):
        """I'm the 'x' property."""
        return self._x
    @x.setter
    def x(self, value):
        self._x = value
    @x.deleter
    def x(self):
        del self._x
if __name__ == '__main__':
    c = C()
    # getter
    print(c.x)  # zhangsan
    print(c.__dict__)  # {'_x': 'zhangsan'}
    # setter
    c.x = "lisi"
    print(c.__dict__)  # {'_x': 'lisi'}
    # deleter
    del c.x
    print(c.__dict__)  # {}