为什么在定义函数时不能使用之前赋值的变量？

Question

下面是我尝试用来运行函数的python代码。

def list_benefits():
    return "More organized code", "More readable code", "Easier code 
    `reuse", "Allowing programmers to share and connect code together"`


def build_sentence(benefit):
    return "%s is a benefit of functions!" %benefit


def name_the_benefits_of_functions():
    list_of_benefits = list_benefits()
    for benefi in list_of_benefits:
        print(build_sentence(benefi))


name_the_benefits_of_functions()

我不明白为什么我们需要变量'list_of_benefits‘，为什么我们不能在最后一个函数中直接使用'list_benefits’。上面的代码运行良好，但是如果我从任何地方删除'list_of_benefits‘，我会得到下面的错误-

TypeError：“function”对象不可迭代

Answer 1

您可以在循环中直接使用list_benefits()。查看以下代码：

def list_benefits():
    return "More organized code", "More readable code", "Easier code","reuse", "Allowing programmers to share and connect code together"

def build_sentence(benefit):
    return "%s is a benefit of functions!" %benefit

def name_the_benefits_of_functions():
    for benefi in list_benefits():
        print(build_sentence(benefi))

name_the_benefits_of_functions()

它对我来说工作得很好。输出：

More organized code is a benefit of functions!
More readable code is a benefit of functions!
Easier code is a benefit of functions!
reuse is a benefit of functions!
Allowing programmers to share and connect code together is a benefit of functions!

如果你想这样做，请不要这样做(我相信你很可能在尝试这样做时遇到了错误)：

for benefi in list_benefits:

这对你不起作用，因为在这种情况下，list_benifits变成了一个变量，而不是一个函数。所以它会产生一个错误。