除了 ValueError 在我的代码中不起作用我不知道为什么答案

【问题标题】：except ValueError isnt working in my code i dont know why除了 ValueError 在我的代码中不起作用我不知道为什么
【发布时间】：2019-05-21 14:14:33
【问题描述】：

我包含 ValueError 以确保用户输入一个整数，但它声明未绑定的本地错误并声明在分配之前引用了变量

def bagTotal():
    while True:
        try:
            bagCount = int(input("Now we just need the number of bags you wish to take with you: "))          
        except ValueError:
            print("Please input a number")
            print("")
        if (bagCount <= 2):
            print("As stated before the first bag is free")
            print(name,",your total is","$%>2F"%ticket)
            print("")
            print("")
            restart()
        else:
            bagTotal = (bagCount - 1) * bagFee
            ticketTotal = bagTotal + ticketamount
            print(name,", your new total is","$%.2f"%ticketTotal)
            print("")
            print("")
            restart()

【问题讨论】：

请发布一些代码并指出它是什么语言。就你的问题而言，我不知道你在讨论什么。
我在使用 python 时表现不佳，我不确定如何发布我之前尝试过的代码，但结果很奇怪
您需要选择您的代码并按下工具栏上的 {} 按钮，或者手动将所有内容缩进四个空格。尝试发布，如果不完美，希望有人会整理它。
好的，谢谢刚刚发布的代码
我添加了[python] 标签，这样代码就会被着色。一个快速的解决方法是将continue 添加为except 块的最后一行，以便您跳转到循环的开头。

标签： python python-3.x valueerror

【解决方案1】：

这是修改后的代码，请检查，我已经注释了几行并且还使用了一些变量我在你的代码中看到了让它在我的系统中工作。

def bagTotal():
    # The below 4 initializations are just
    # to stop errors in your problem, you use your own values
    bagFee = 100      
    ticketamount = 60 
    name = 'Rampel Jons'
    ticket = 70

    while True:
        try:
            bagCount = int(input("Now we just need the number of bags you wish to take with you: "))          
            if (bagCount <= 2):
                print("As stated before the first bag is free")
                print(name,",your total is","$%>2F"%ticket)
                print("")
                print("")
                restart() 
            else:
                bagTotal = (bagCount - 1) * bagFee
                ticketTotal = bagTotal + ticketamount
                print(name,", your new total is","$%.2f"%ticketTotal)
                print("")
                print("")
                restart() 
        except ValueError:
            print("Please input a number")
            print("")

# call
bagTotal()

# Now we just need the number of bags you wish to take with you: 5
# Rampel Jons , your new total is $460.00


# Now we just need the number of bags you wish to take with you: 7
# Rampel Jons , your new total is $660.00


# Now we just need the number of bags you wish to take with you: 9
# Rampel Jons , your new total is $860.00


# Now we just need the number of bags you wish to take with you: fjjfjf
# Please input a number

# Now we just need the number of bags you wish to take with you:

【讨论】：

对不起，这只是我的代码的一部分，还有另一个名为 restart() 的 mod，它让用户可以选择为不同的票输入更多的包

【解决方案2】：

如果您遇到 ValueError，程序将继续运行您的 if 语句等，然后再进入 while 循环的下一个循环。如果您没有收到错误，您只希望该代码运行，因此您的代码应如下所示：

def bagTotal():
    while True:
        try:
            bagCount = int(input("Now we just need the number of bags you wish to take with you: "))
            if (bagCount <= 2):
                print("As stated before the first bag is free")
                print(name,",your total is","$%>2F"%ticket)
                print("")
                print("")
                restart()
            else:
                bagTotal = (bagCount - 1) * bagFee
                ticketTotal = bagTotal + ticketamount
                print(name,", your new total is","$%.2f"%ticketTotal)
                print("")
                print("")
                restart()          
        except ValueError:
            print("Please input a number")
            print("")

【讨论】：