python decorators(TypeError: 'NoneType' object is not an iterator)

Question

下面是我的装饰器和协同程序的 python 程序，

#coroutine decorator    
def coroutine_decorator(coroutine_func):
    def wrapper(*args,**kwargs):
    c=coroutine_func(*args,**kwargs)
    next(c)
    return c
return wrapper

# Define the coroutine function 'linear_equation' below
@coroutine_decorator
def linear_equation(a, b):
    while True:
        x=yield
        e=a*(x**2)+b
        print("Expression, {0}*x^2 + {1}, with x being {2} equals {3}".format(int(a),x,int(b),int(e)))

# Define the coroutine function 'numberParser' below
@coroutine_decorator
def numberParser():
    equation1 = linear_equation(3, 4)
    equation2 = linear_equation(2, -1)
# code to send the input number to both the linear equations
    equation1.send(6.0)
    equation2.send(6.0)


def main(x):
    n = numberParser()
    n.send(x)


if __name__ == "__main__":
    x = float(input())

我收到运行时错误，我可以理解出了什么问题，但不确定为什么我收到 TypeError: 'NoneType' object is not an iterator

Traceback (most recent call last):
File "solution.py", line 42, in <module>
res = main(x);
File "solution.py", line 34, in main
n = numberParser()
File "solution.py", line 10, in wrapper
next(c)
TypeError: 'NoneType' object is not an iterator 

Answer 1

由于您在装饰函数上调用next ，所以大概您只能装饰一个函数，如果它是一个生成器或者它返回一个迭代器。 numberParser不包含yield语句，也不返回任何内容，因此不符合这些要求。

您应该修改numberParser以便它产生一些东西，或者它返回一个迭代器。

Answer 2

numberParser协程不会为例程屈服

调整

# code to send the input number to both the linear equations
    equation1.send(6.0)
    equation2.send(6.0)

到

# code to send the input number to both the linear equations
while True :
        x = yield
        equation1.send(x)
        equation2.send(x)

Answer 3

下面的代码为我工作

# Define the function 'coroutine_decorator' below
def coroutine_decorator(coroutine_func):
    def wrapper(*args, **kwdargs):
        c = coroutine_func(*args, **kwdargs)
        next(c)
        return c
    return wrapper

# Define coroutine 'linear_equation' as specified in previous exercise
@coroutine_decorator
def linear_equation(a, b):
    while True:
        x = yield
        e = a*(x**2)+b
        print('Expression, '+str(a)+'*x^2 + '+str(b)+', with x being '+str(x)+' equals '+str(e))
  

# Define the coroutine function 'numberParser' below
@coroutine_decorator
def numberParser():
    equation1 = linear_equation(3, 4)
    equation2 = linear_equation(2, -1)
    # code to send the input number to both the linear equations
    while True:
        x = yield
        equation1.send(x)
        equation2.send(x)

您为包装器 Def 错误地编写了以下代码。 定义 C 变量和下面的步骤是 sub def 包装器的一部分。

    def coroutine_decorator(coroutine_func):
        def wrapper(*args, **kwdargs):
        c = coroutine_func(*args, **kwdargs)
        next(c)
        return c
    return wrapper

然后我在 numberParse Def 中添加了以下块

while True:
    x = yield
    equation1.send(x)
    equation2.send(x)

Answer 4

你非常接近答案。 记住协程的最基本的：

协程在到达 yield 语句时停止执行

因此，您需要做的就是像这样在 equation1 和 equation2 上调用 yield：

equation1.send(x)
equation2.send(x)
equation1 = yield
equation2 = yield

Answer 5

试试这个。 这在主要功能之前对我有用：

# Define 'coroutine_decorator' below
def coroutine_decorator(coroutine_func):
    def wrapper(*args,**kwargs):
        c=coroutine_func(*args,**kwargs)
        next(c)
        return c
    return wrapper
    
# Define coroutine 'linear_equation' as specified in previous exercise
@coroutine_decorator
def linear_equation(a, b):
    while True:
        x=yield
        e=a*(x**2)+b
        print("Expression, {0}*x^2 + {2}, with x being {1} equals {3}".format(int(a),x,int(b),float(e)))
        
# Define the coroutine function 'numberParser' below
@coroutine_decorator
def numberParser():
    equation1 = linear_equation(3, 4)
    equation2 = linear_equation(2, -1)
    # code to send the input number to both the linear equations
    while True :
        x = yield
        equation1.send(x)
        equation2.send(x)
    
def main(x):
    n = numberParser()
    n.send(x)