Question

在尝试实现类级别的缓存装饰器时，我偶然发现了ring库，该库能够全局存储函数的输入和输出。给定class的{{1}}定义，基本上可以实现以下行为：

Calculate

这是我尝试通过import ring class Calculate: @ring.dict({}) def sum(self, a, b): print('actually calculating') sum = a + b return sum

实现的行为

Calculate

现在，我需要使用>>> calculate = Calculate() >>> calcualte.sum(5,7) actually calculating 12 >>> different_calculate = Calculate() >>> different_calculate.sum(5,7) 12 #this outputs 12 straight from the cache from first calculate. #Note that even if 'different_calculate' and 'calculate' are different instantiations of 'Calculate', the cache works at a class level. Therefore the sum is not actually REcalculated.实现相同的行为，这次是一个属性。我在这里面临的问题是，在sum @property中将def作为参数。因此，当尝试像上一个示例中那样进行缓存时，它将不起作用，因为输入不再是self和num1而是num2，它随每个实例化而改变。因此，它永远不会在不同的类实例上从缓存中拉出，因为self总是随每个实例而变化。见下文：

self

要解决此问题，我必须以某种方式告诉缓存库不要将import ring class Calculate: def __init__(self, num1, num2): self.num1 = num1 self.num2 = num2 @ring.dict({}) @property def sum(self): print('actually calculating') sum = num1 + num2 return sum >>> calculate = Calculate() >>> calcualte.sum(5,7) actually calculating 12 >>> different_calculate = Calculate() >>> different_calculate.sum(5,7) actually calculating 12作为输入，而是将self，self.num1视为输入。然后代码将变成这样：

self.num2

我可以用@ring.dict(self.num1, self.num2) # <--- this does not exist @property def sum(self): print('actually calculating') sum = num1 + num2 return sum或其他任何python缓存库来实现此目的吗？

Answer 1

因此，从here得到一些启发之后，我最终只是创建了自己的记忆功能，如下所示：

memo = {}

def memoize(*attrs):  
    def wrapper(f):  
        def helper(obj):
            key = tuple([getattr(obj,attr) for attr in attrs])
            if key not in memo:            
                memo[key] = f(obj)
            return memo[key]
        return helper
    return wrapper




class Calculate:
    def __init__(self, num1, num2):
        self.num1 = num1
        self.num2 = num2

    @property
    @memoize('num1', 'num2')  
    def sum(self):
        print('actually calculating')
        sum = self.num1 + self.num2
        return sum


>>> calculate = Calculate(6,9)
>>> calculate.sum
actually calculating
15

>>> another_calculate = Calculate(6,9)
>>> another_calculate.sum
15

具有特定对象属性的全局缓存作为python

1 个答案: