减少尝试的数量和除python

Question

我已经为ATM构建了一个程序，该程序可以检查用户的PIN，然后撤回资金。如果用户的引脚不匹配，则锁定卡。但是，如果确实匹配，它要求用户投入一定数量。如果用户投入的金额不是数字，则提示用户将正确的金额放入，如果用户放入的金额大于其余额大的余额，则会引起错误并退出程序。如果用户投入的金额低于余额，则其撤回资金。我使用了多个例外，但我相信我的代码看起来太令人费解了。有什么更好的方法可以简化我的代码？使用更少的尝试和除外？ 还是使用不同的功能进行不同的动作？

user = {
    'pin': 1234,
    'balance': 100
}


def withdraw_cash():
    while True:
        try:
            amount = int(input("Enter the amount of money you want to withdraw: "))
        except ValueError as v:
            print(f"Enter correct amount: ")

        else:
            if amount > user['balance']:
                raise ValueError("You don't have sufficient balance to make this withdrawal")
                is_quit = True

            else:
                user['balance'] = user['balance'] - amount
                print(f"£{amount} successfully withdrawn your remaining balance is £{user['balance']}")
                print('')
                return "Thank you for using Bankomat ATM"

        # finally:
        # print("Program executed")


def bank_atm():
    count = 0
    while count < 3:
        try:
            pin = int(input('Please enter your four digit pin: '))
        except ValueError:
            print("Please enter correct pin")
            count += 1
        else:
            try:
                if pin != user['pin']:
                    print("Pin does not match.. Try Again")
                    count += 1
                else:
                    try:
                        withdraw_cash()
                        return "Thank you for using Bankomat ATM"
                    except ValueError as v:
                        raise v
            except ValueError as v:
                raise v

    if count == 3:
        print('3 UNSUCCESFUL PIN ATTEMPTS, EXITING')
        print('!!!!!YOUR CARD HAS BEEN LOCKED!!!!!')
        is_quit = True
    return "Thank you for using Bankomat ATM"


try:
    bank_atm()
except ValueError as v:
    print(f"ERROR: {v}")

Answer 1

我设法将其简化为奏效！
现在，我将看看是否可以将代码分解为较小的功能，以便可以运行单元测试。

user = {
    'pin': 1234,
    'balance': 100
}


def withdraw_cash():
    while True:
        try:
            amount = int(input("Enter the amount of money you want to withdraw: "))
        except ValueError as v:
            print(f"Enter correct amount: ")
        else:
            if amount > user['balance']:
                raise ValueError("You don't have sufficient balance to make this withdrawal")  
            else:
                user['balance'] = user['balance'] - amount
                print(f"£{amount} successfully withdrawn your remaining balance is £{user['balance']}")
                print('')
                return 
        finally:
            print("Program executed")

def bank_atm():
    count = 0
    to_exit = False
    while (count < 3) and (not to_exit):
        try:
            pin = int(input('Please enter your four digit pin: '))
            print("this worked")
        except ValueError:
            print("Please enter correct pin")
            count += 1
        if pin != user['pin']:
            print("Pin does not match.. Try Again")
            count += 1
        else:
            withdraw_cash()
            to_exit = True
    if count == 3:
        print('3 UNSUCCESFUL PIN ATTEMPTS, EXITING')
        print('!!!!!YOUR CARD HAS BEEN LOCKED!!!!!')
    


try:
    bank_atm()
except ValueError as v:
    print(f"ERROR: {v}")

Answer 2

您可以通过IF-Else语句和一个计数器来实现这一切。

user = {
    'pin': 1234,
    'balance': 100
}

def withdraw_cash():
    while True:
        amount = input("Enter the amount of money you want to withdraw: ")
        if not int(amount):
            print(f"Enter correct amount: ")
        else:
            amount = int(amount)
            if amount > user['balance']:
                raise ValueError("You don't have sufficient balance to make this withdrawal")
                is_quit = True

            else:
                user['balance'] = user['balance'] - amount
                print(f"£{amount} successfully withdrawn your remaining balance is £{user['balance']}")
                print('')
                return "Thank you for using Bankomat ATM"


def main():
    count = 0
    while count < 3:
        pin = input('Please enter your four digit pin: ')
        if not int(pin):
            print("Please enter correct pin")
            count += 1
        else:
            pin = int(pin)
            if pin != user['pin']:
                print("Pin does not match.. Try Again")
                count += 1
            else:
                print(withdraw_cash())
                raise SystemExit

    if count == 3:
        print('3 UNSUCCESFUL PIN ATTEMPTS, EXITING')
        print('!!!!!YOUR CARD HAS BEEN LOCKED!!!!!')
        is_quit = True
    return "Thank you for using Bankomat ATM"


main()