Hello
I wrote a decorator to add a cache to functions.
I realized that cache dictionnary could be defined
as an object attribute or as a local variable in
method __call__.
Both seems to work properly.
Can you see any differences between the two variants ?
from collection import OrderedDict
class Memoize1:
def __init__(self, size=None):
self.size = size
self.cache = OrderedDict() ### cache defined as an attribute
def __call__(self, f):
def f2(*arg):
if arg not in self.cache:
self.cache[arg] = f(*arg)
if self.size is not None and len(self.cache) >self.size:
self.cache.popitem(last=False)
return self.cache[arg]
return f2
# variant
class Memoize2:
def __init__(self, size=None):
self.size = size
def __call__(self, f):
cache = OrderedDict() ### cache defined as a local variable
def f2(*arg):
if arg not in cache:
cache[arg] = f(*arg)
if self.size is not None and len(cache) > self.size:
cache.popitem(last=False)
return cache[arg]
return f2
@Memoize1(16)
def fibo1(n):
if n < 2: return n
return fibo1(n-2)+fibo1(n-1)
@Memoize2(16)
def fibo2(n):
if n < 2: return n
return fibo2(n-2)+fibo2(n-1)
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