python - 当变量在别处发生变化时如何更新类的列表或字典？

Question

如何在外部更改后更新包含其他 self.variables 的 self.dictionary 或 self.list？

例如我们有下面的测试类:

class Test():
   def __init__(self):
       self.some_number = 0
       self.other_number = 0
       self.lst=[self.some_number, self.other_number]
       self.dic={'some_number': self.some_number, 'other_number': self.other_number}

   def update_values(self):
       self.number = 2
       self.other_number = 3

然后更新值:

test = Test()                  

print(test.dic)
print(test.lst)

test.update_values()

print(test.dic) 
print(test.lst)

结果没有变化:

{'other_number': 0, 'some_number': 0}
[0, 0]
{'other_number': 0, 'some_number': 0}
[0, 0]

我实际上认为，字典和列表包含对这些指向内存中某处的变量的引用。因此，如果这些发生变化，那也应该发生变化。但事实似乎并非如此。有什么解释吗？

Answer 1

如果您想在使用 self.lst 或 self.dic 时获得更新的值，请将它们设为 property :

class Test():
    def __init__(self):
        self.some_number = 0
        self.other_number = 0

    def update_values(self):
        self.some_number = 2
        self.other_number = 3

    @property
    def lst(self):
        return [self.some_number, self.other_number]

    @property
    def dic(self):
        return {'some_number': self.some_number,
                'other_number': self.other_number}

>>> t = Test()
>>> t.lst
[0, 0]
>>> t.dic                                                          
{'some_number': 0, 'other_number': 0}
>>> t.update_values()
>>> t.lst                                                          
[2, 3]
>>> t.dic 
{'some_number': 2, 'other_number': 3}