带有列表的Python装饰属性设置器

Question

globalList = []
class MyList:
def init(self):
self._myList = [1, 2, 3]

    @property
    def myList(self):
        return self._myList + globalList
    @myList.setter
    def myList(self, val):
        self._myList = val

mL1 = MyList()
print("myList: ", mL1.myList)
mL1.myList.append(4)
print("after appending a 4, myList: ", mL1.myList)
mL1.myList.extend([5,6,"eight","IX"])
print("after extend, myList: ", mL1.myList)

结果：

myList:  [1, 2, 3]
after appending a 4, myList:  [1, 2, 3]
after extend, myList:  [1, 2, 3]

我面临的问题是mL1.myList.append（4）和mL1.myList.extend（[5,6，“ eight”，“
IX”]）不会修改mL1对象中的_myList属性。我该如何解决该问题？

Answer 1

我为类对象定义了方法append（）和方法extend（）。它分别追加到成员myList并扩展成员myList。

global globalList  
globalList = []
class MyList():
    def __init__(self):
        self._myList = [1, 2, 3]

    @property
    def myList(self):
        return self._myList + globalList
    @myList.setter
    def myList(self, val):
        self._myList = val

    def append(self, val):
        self.myList = self.myList + [val]
        return self.myList

    def extend(self, val):
        return self.myList.extend(val)


mL1 = MyList()
print("myList: ", mL1.myList)
mL1.append(4)
print("after appending a 4, myList: ", mL1.myList)
mL1.myList.extend([5,6,"eight","IX"])
print("after extend, myList: ", mL1.myList)

结果是

>>> 
('myList: ', [1, 2, 3])
('after appending a 4, myList: ', [1, 2, 3, 4])
('after extend, myList: ', [1, 2, 3, 4, 5, 6, 'eight', 'IX'])