python - 调用此内存函数会引发 TypeError : unhashable type: 'dict'

Question

我有这个代码，当我打印它时，我遇到了这个错误。有人可以告诉我如何解决这个问题吗？

def memoize(func):
    """Store the results of the decorated function for fast lookup
    """
    # Store results in a dict that maps arguments to results
    cache = {}
    def wraper(*args, **kwargs):
        if (args, kwargs) not in cache:
            cache[(args, kwargs)] = func(*args, **kwargs)
        return cache[(args, kwargs)]
    return wraper

@memoize 
def slow_function(a, b):
    print('Sleeping...')
    time.sleep(5)
    return a + b

print(slow_function(3,4))

错误:类型错误:不可散列的类型:'dict'

Answer 1

这里有一个简单的方法来避免该问题，即将 kwargs 字典转换为字符串(以及 args)，以生成可接受的字典键。

我从 Memoize 得到了这个想法Python Decorator Library 部分.

import time

def memoize(func):
    """Store the results of the decorated function for fast lookup
    """
    # Store results in a dict that maps arguments to results
    cache = {}
    def wrapper(*args, **kwargs):
        key = str(args) + str(kwargs)
        if key not in cache:
            cache[key] = func(*args, **kwargs)
        return cache[key]
    return wrapper

@memoize
def slow_function(a, b):
    print('Sleeping...')
    time.sleep(5)
    return a + b

print(slow_function(3,4))