>>> class Lemons():
        def __init__(self,unit_price=7):
            self.unit_price = unit_price
        def get_unit_price(self):
            return self.unit_price
        def set_unit_price(self,new_unit_price):
            self.unit_price = new_unit_price
        def del_unit_price(self):
            del self.unit_price
        x = property(get_unit_price, set_unit_price, del_unit_price)
>>> fruit = Lemons()
>>> 
>>> fruit.x                         #調(diào)用 fruit.x 觸發(fā) get_unit_price
7
>>> 
>>> fruit.x = 9                     #調(diào)用 fruit.x = 9 觸發(fā) set_unit_price
>>> 
>>> fruit.x
9
>>> 
>>> fruit.unit_price                #調(diào)用 fruit.unit_price 觸發(fā) get_unit_price
9
>>> del fruit.x                     #調(diào)用 del fruit.x 觸發(fā) del_unit_price 
>>> 
>>> fruit.unit_price
Traceback (most recent call last):
  File "<pyshell#23>", line 1, in <module>
    l.unit_price
AttributeError: 'Lemons' object has no attribute 'unit_price'

 class People:
     def __init__(self, name, weight, height):
         self.name = name
         self.weight = weight
         self.height = height
# 定義函數(shù)的原因1：
# 1、從bmi的公式上看，bmi應(yīng)該是觸發(fā)功能計(jì)算得到的
# 2、bmi是隨著身高、體重的變化而動(dòng)態(tài)變化的，不是一個(gè)固定的值
#    說(shuō)白了，每次都是需要臨時(shí)計(jì)算得到的
# 但是bmi聽(tīng)起來(lái)更像是一個(gè)數(shù)據(jù)屬性，而非功能
	 @property
	 def bmi(self):
		return self.weight / (self.height ** 2)
 obj1 = People('egon', 70, 1.83)
 print(obj1.bmi())
 obj1.height=1.86
 print(obj1.bmi())
 print(obj1.bmi)

'''
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'''
 class People:
     def __init__(self, name):
         self.__name = name
     def get_name(self):
         return self.__name
     def set_name(self, val):
         if type(val) is not str:
             print('必須傳入str類型')
             return
         self.__name = val
     def del_name(self):
         print('不讓刪除')
         # del self.__name
     name=property(get_name,set_name,del_name)
 obj1=People('egon')
 # print(obj1.get_name())
 # obj1.set_name('EGON')
 # print(obj1.get_name())
 # obj1.del_name()
 # 人正常的思維邏輯
 print(obj1.name) #
 # obj1.name=18
 # del obj1.name

class People:
    def __init__(self, name):
        self.__name = name
    @property
    def name(self): # obj1.name
        return self.__name
    @name.setter
    def name(self, val): # obj1.name='EGON'
        if type(val) is not str:
            print('必須傳入str類型')
            return
        self.__name = val
    @name.deleter
    def name(self): # del obj1.name
        print('不讓刪除')
        # del self.__name
obj1=People('egon')
# 人正常的思維邏輯
print(obj1.name) #
# obj1.name=18
# del obj1.name