Question

我包含ValueError以确保用户输入一个整数，但是它声明了未绑定的本地错误，并指出在赋值之前已引用了变量

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()

Answer 1

如果要获取ValueError，该程序将继续并运行if语句，等等，然后转到while循环的下一个循环。您只希望在没有错误的情况下运行该代码，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，我注释了几行，还使用了一些变量我在您的代码中看到可以使其在我的系统中正常工作。

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:

除了ValueError在我的代码中不起作用我不知道为什么

2 个答案: