python 裝飾器實作緩存_我怎麼能寫python裝飾器進行緩存？

>您應該記住@decorator隻是func = decorator(func)的文法糖.是以這裡有一個差別：

(1)

@decorator

def func():

...

和…一樣

func = decorator(func) # Just call of __init__

func(...) # Call of decorator.__call__

但(2)

@decorator(some_param)

def func():

...

類似于

# Call of __init__ plus call of __call__

func = decorator(some_param)(func)

# Call of closure returned by decorator.__call__

func(...)

>您已經為(2)文法實作了裝飾器接受參數,但在使用它們時不提供它們,如示例(1)所示.這就是為什麼__init__抱怨,它接收func作為第二個參數.

>您應該在包裝器閉包中編寫self.cache,是以包裝器将引用相應的裝飾器對象.寫入緩存将導緻全局變量搜尋,是以将失敗.

UPD：我改變你的代碼接近(1)：

class memoize:

def __init__(self, function):

self.cache = {}

self.function = function

def __call__(self, *args, **kwargs):

key = str(args) + str(kwargs)

if key in self.cache:

return self.cache[key]

value = self.function(*args, **kwargs)

self.cache[key] = value

return value

@memoize

def fib(n):

if n in (0, 1):

return 1

else:

return fib(n-1) + fib(n-2)

for i in range(0, 10):

print(fib(i))

print(fib.cache)