为什么 if/else 语句在我的函数中不起作用？

Question

我正在使用 if/else 语句供用户选择客户选项（居民或企业），输入他们使用的千瓦数，程序将计算电费。这必须在函数中使用（我们在 class 中学习的一章）。这是我的代码：

def main():
    customer = input("Enter R for residential or B for business")
    hours = int(input("Enter number of khw"))
    bill_calculator(hours, customer)


def bill_calculator(kwh,customer):
    if customer == 'R' :
        if kwh < 500:
            normal_amount = kwh * .12
        print ("Please pay this amount: ", normal_amount)
    elif kwh > 500:
        over_amount = kwh * .15
        print("Please pay this amount",over_amount)

    if customer == 'B':
        if kwh < 800:
            business_amount = kwh * .16
        print("Please pay this amount: ")
    elif kwh > 800:
        business_amount = kwh * .2
    print("Please pay this amount,", business_amount)

    main()

我的 "resident" 计算有效并显示，但 "business" 计算无效。我觉得这与我的缩进有关，但我不知道在哪里。

下面是我的错误：

Enter R for residential or B for businessR
Enter number of khw77
Please pay this amount:  9.24
Traceback (most recent call last):
  File "C:/Users/vanbe/PycharmProjects/Lesson7/L07P2.py", line 24, in <module>
    main()
  File "C:/Users/vanbe/PycharmProjects/Lesson7/L07P2.py", line 4, in main
    bill_calculator(hours, customer)
  File "C:/Users/vanbe/PycharmProjects/Lesson7/L07P2.py", line 22, in bill_calculator
    print("Please pay this amount,", business_amount)
UnboundLocalError: local variable 'business_amount' referenced before assignment

谢谢大家

Answer 1

您的代码至少存在三个问题。首先，正如 juanpa.arrivillaga 在评论中提到的那样，您在每种情况下都打印 business_amount ，但仅在 customer == 'B'

时分配

其次，如果 'R' 客户的千瓦时等于 500，'B' 客户的千瓦时等于 800，则您没有分配。

最后，看起来 elif kwh > 500 与 kwh < 500 处于同一水平。

您可能希望您的代码看起来像这样：

    if customer == 'R' :
        if kwh < 500:
            normal_amount = kwh * .12
            print ("Please pay this amount: ", normal_amount)
        elif kwh >= 500:
            over_amount = kwh * .15
            print("Please pay this amount",over_amount)

为什么 if/else 语句在我的函数中不起作用？

Why do the if/else statements not work within my function?

python

main

if-statement

function

definition