除了 ValueError 在我的代码中不起作用我不知道为什么

Question

我包含了 ValueError 以确保用户输入一个整数，但它指出未绑定的本地错误并指出变量在赋值之前被引用

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()

Answer 1

如果您得到一个 ValueError，程序将继续并且运行您的 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，您只希望该代码为运行，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("")

Answer 2

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您的代码中看到它可以在我的系统中运行。

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 0.00


# Now we just need the number of bags you wish to take with you: 7
# Rampel Jons , your new total is 0.00


# Now we just need the number of bags you wish to take with you: 9
# Rampel Jons , your new total is 0.00


# 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:

除了 ValueError 在我的代码中不起作用我不知道为什么

except ValueError isnt working in my code i dont know why

python

python-3.x

valueerror