Python 递归函数修饰器

发布于03月20日

我想实现递归函数的修饰器，即纤维数字， idea 是，如你所知，大输入的递归函数需要太多的时间，对于这个例子，我try 了斐波纳契数字，但它返回以下错误: TypeError: unsupported operand type(s) for +: 'NoneType' and 'NoneType'个

如果我在没有decorator的情况下运行代码，它工作得很好，并返回相应的输出，但是使用decorator会引发错误，

           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)

请帮助我了解我的代码有什么问题？

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 递归函数修饰器

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