递归函数的装饰器

问题描述 投票：0回答：1

我想实现递归函数的装饰器，即斐波那契数，想法是，正如你所知，大输入的递归函数需要太多时间，对于这个例子，我尝试了斐波那契数，但它返回以下错误： 

 TypeError: unsupported operand type(s) for +: 'NoneType' and 'NoneType'

如果我在没有装饰器的情况下运行代码，它工作正常并返回相应的输出，但是使用装饰器它会引发错误，我也会发布代码

           import time
            # start =time.time()
            def time_calculator(func):
                def n_th_number(n):
                    start = time.time()
            
                    print(func(n))
                    end = time.time()
                    print(f'fibonacci lasts for {end - start} second')
                return n_th_number
            @time_calculator
            def fibonacci(n):
                if n==0 or n==1:
                    return n
                else:
            
                   return fibonacci(n-1)+fibonacci(n-2)
            fibonacci(30)

请帮助我理解我的代码有什么问题？

完全错误：

1
fibonacci lasts for 0.0 second
0
fibonacci lasts for 0.0 second
Traceback (most recent call last):
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 16, in <module>
    fibonacci(30)
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 7, in n_th_number
    print(func(n))
          ^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 15, in fibonacci
    return fibonacci(n-1)+fibonacci(n-2)
           ^^^^^^^^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 7, in n_th_number
    print(func(n))
          ^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 15, in fibonacci
    return fibonacci(n-1)+fibonacci(n-2)
           ^^^^^^^^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 7, in n_th_number
    print(func(n))
          ^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 15, in fibonacci
    return fibonacci(n-1)+fibonacci(n-2)
           ^^^^^^^^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 7, in n_th_number
    print(func(n))
          ^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 15, in fibonacci
    return fibonacci(n-1)+fibonacci(n-2)
           ^^^^^^^^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 7, in n_th_number
    print(func(n))
          ^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 15, in fibonacci
    return fibonacci(n-1)+fibonacci(n-2)
           ^^^^^^^^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 7, in n_th_number
    print(func(n))
          ^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 15, in fibonacci
    return fibonacci(n-1)+fibonacci(n-2)
           ^^^^^^^^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 7, in n_th_number
    print(func(n))
          ^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 15, in fibonacci
    return fibonacci(n-1)+fibonacci(n-2)
           ^^^^^^^^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 7, in n_th_number
    print(func(n))
          ^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 15, in fibonacci
    return fibonacci(n-1)+fibonacci(n-2)
           ^^^^^^^^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 7, in n_th_number
    print(func(n))
          ^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 15, in fibonacci
    return fibonacci(n-1)+fibonacci(n-2)
           ^^^^^^^^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 7, in n_th_number
    print(func(n))
          ^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 15, in fibonacci
    return fibonacci(n-1)+fibonacci(n-2)
           ^^^^^^^^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 7, in n_th_number
    print(func(n))
          ^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 15, in fibonacci
    return fibonacci(n-1)+fibonacci(n-2)
           ^^^^^^^^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 7, in n_th_number
    print(func(n))
          ^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 15, in fibonacci
    return fibonacci(n-1)+fibonacci(n-2)
           ^^^^^^^^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 7, in n_th_number
    print(func(n))
          ^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 15, in fibonacci
    return fibonacci(n-1)+fibonacci(n-2)
           ^^^^^^^^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 7, in n_th_number
    print(func(n))
          ^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 15, in fibonacci
    return fibonacci(n-1)+fibonacci(n-2)
           ^^^^^^^^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 7, in n_th_number
    print(func(n))
          ^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 15, in fibonacci
    return fibonacci(n-1)+fibonacci(n-2)
           ^^^^^^^^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 7, in n_th_number
    print(func(n))
          ^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 15, in fibonacci
    return fibonacci(n-1)+fibonacci(n-2)
           ^^^^^^^^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 7, in n_th_number
    print(func(n))
          ^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 15, in fibonacci
    return fibonacci(n-1)+fibonacci(n-2)
           ^^^^^^^^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 7, in n_th_number
    print(func(n))
          ^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 15, in fibonacci
    return fibonacci(n-1)+fibonacci(n-2)
           ^^^^^^^^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 7, in n_th_number
    print(func(n))
          ^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 15, in fibonacci
    return fibonacci(n-1)+fibonacci(n-2)
           ^^^^^^^^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 7, in n_th_number
    print(func(n))
          ^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 15, in fibonacci
    return fibonacci(n-1)+fibonacci(n-2)
           ^^^^^^^^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 7, in n_th_number
    print(func(n))
          ^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 15, in fibonacci
    return fibonacci(n-1)+fibonacci(n-2)
           ^^^^^^^^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 7, in n_th_number
    print(func(n))
          ^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 15, in fibonacci
    return fibonacci(n-1)+fibonacci(n-2)
           ^^^^^^^^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 7, in n_th_number
    print(func(n))
          ^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 15, in fibonacci
    return fibonacci(n-1)+fibonacci(n-2)
           ^^^^^^^^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 7, in n_th_number
    print(func(n))
          ^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 15, in fibonacci
    return fibonacci(n-1)+fibonacci(n-2)
           ^^^^^^^^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 7, in n_th_number
    print(func(n))
          ^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 15, in fibonacci
    return fibonacci(n-1)+fibonacci(n-2)
           ^^^^^^^^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 7, in n_th_number
    print(func(n))
          ^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 15, in fibonacci
    return fibonacci(n-1)+fibonacci(n-2)
           ^^^^^^^^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 7, in n_th_number
    print(func(n))
          ^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 15, in fibonacci
    return fibonacci(n-1)+fibonacci(n-2)
           ^^^^^^^^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 7, in n_th_number
    print(func(n))
          ^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 15, in fibonacci
    return fibonacci(n-1)+fibonacci(n-2)
           ^^^^^^^^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 7, in n_th_number
    print(func(n))
          ^^^^^^^
  File "C:\Users\User\PycharmProjects\New_AI_Era\time_estimation.py", line 15, in fibonacci
    return fibonacci(n-1)+fibonacci(n-2)
           ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~
TypeError: unsupported operand type(s) for +: 'NoneType' and 'NoneType'
python recursion python-decorators
1个回答
0
投票

包装器仍然需要调用该函数并返回它本应返回的值。

           import time
            # start =time.time()
            def time_calculator(func):
                def n_th_number(n):
                    start = time.time()
                    result = func(n)
                    print(result)
                    end = time.time()
                    print(f'fibonacci lasts for {end - start} second')
                    return result
                return n_th_number
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