Python - 将 function 值转换为 int 或 float 以进行比较

Question

所以本质上，我正在模拟一个钱箱，我在其中接收硬币并建立用户信用，然后当用户请求购买物品时，我检查以确保他们有足够的信用来购买该物品。

我遇到的问题是，当我到达 haveYou function 时，我尝试比较两个值 price 和 credit 在当前版本的代码中，self.price 在 CashBox 中设置为 35。 init ，以便 Selector.select() 中的 if 语句正常工作。

如果我在 init function 中包含 self.price = 0，它会保持该值并表示信用和价格相等，因此如果我尝试返回 self.credit >= self.price，它会继续，引用 getPrice 方法的返回，它说我无法将 int 与 function 值进行比较。 我已经检查过了，这绝对是 self.price 的问题。

所以我的问题是，如何将 function 值转换为 int，或者将 getPrice 的返回值设置为 int 开头？ 我已经看过了，但是互联网上充满了 int 以浮动到字符串的东西，我找不到任何关于这个的东西。 我在这个桌子上敲了大约 5 个小时的头，非常感谢您的帮助。 谢谢

import time
import sys

class CashBox(object):
    def __init__(self):
        self.credit = 0
        self.totalReceived = 0
        #self.price = 35

    def deposit(self,amount):
        self.credit = amount + self.credit
        self.totalReceived = amount + self.totalReceived
        print(self.credit)
        print(type(self.credit))
        return self.credit

    def returnCoins(self):
        print("Returning ", self.credit/100, " dollars.")
        self.totalReceived = 0

    def haveYou(self,amount):
        price = Product.getPrice
        return self.credit >= price

    def deduct(self,amount):
        pass

    def totalCoins(self):
        return self.totalReceived

class CoffeeMachine(object): 

    def __init__(self):
        self.cashBox = CashBox()
        self.credit = CashBox.__init__
        self.selector = self.cashBox

    def oneAction(self):

        while True:
            command = input("""
            ______________________________________________________
            PRODUCT LIST: all 35 cents, except bouillon (25 cents)
            1=black, 2=white, 3=sweet, 4=sweet & white, 5=bouillon      
            Sample Commands: insert 25, select 1, cancel, quit.
            Your command: 
            """)
            words = command.lower().split()           
            if 'select' in words:
                Selector.select(self,int(words[1]))
            elif 'insert' in words:
                coinsAllowed = [5,10,25,50]
                if int(words[1]) in coinsAllowed:
                    self.cashBox.deposit(int(words[1]))
                else:
                    print("""
                    That is not one of the allowed coins, 
                    please insert a penny, nickel, dime, quarter,
                    or half-dollar. Thank you.
                    """)
            elif 'cancel' in words:
                print("Cancelling transaction. Returning to main menu: ")
                self.cashBox.returnCoins()
            elif 'quit' in words:
                print("Have a nice day!")
                break
            else:
                print("That is not an option")

    def totalCash(self):
        return self.cashBox.totalReceived    

class Product(object):

    def __init__(self,name,price,recipe):
        self.name = name
        self.price = price
        self.recipe = recipe

    def getPrice(self):
        return self.price

    def make(self):
        for item in self.recipe:
            print("dispensing", item)
            time.sleep(0.5)
        print("Enjoy your", self.name)
        time.sleep(0.5)
        print(self.price)

class Selector(object):

    def __init__(self):
        #self.Product = Product()
        self.cashBox = CashBox()
        self.credit = CashBox.deposit
        #self.products.append(Product.

    def select(self, choiceIndex):
        recipes = {
            1 : ["Black coffee",35,["cup", "coffee", "water"]],
            2 : ["White coffee",35,["cup", "coffee", "creamer", "water"]],
            3 : ["Sweet coffee",35,["cup", "coffee", "sugar", "water"]],
            4 : ["White & Sweet coffee",35,["cup", "coffee", "sugar", "creamer", "water"]],
            5 : ["Bouillon",25,["cup bouillonPowder", "water"]]
        }
        if choiceIndex in range(1,len(recipes)+1):
            if self.cashBox.haveYou(self.credit) == True:
                self.choiceIndex = choiceIndex
                self.recipe = recipes.get(choiceIndex)
                #print(self.recipe,"Great selection")
                product = Product(*self.recipe)
                price = CashBox.haveYou(*self.recipe)
                product.make()              
            else:
                print("You don't have enough credit for that, please insert more money.")
        else:
            print("That selection does not exist")

def main():
    m = CoffeeMachine()
    while m.oneAction():
        pass
    total = m.totalCash()
    print(f"Total Cash: ${total/100:.2f}")

if __name__ == "__main__":

取决于我正在尝试：取消注释 self.price = 35

Exception has occurred: AttributeError
'int' object has no attribute 'price'
  File "C:\Users\Tanner Harmer\Desktop\Coffee2\CashBox.py", line 81, in getPrice
    return self.price
  File "C:\Users\Tanner Harmer\Desktop\Coffee2\CashBox.py", line 22, in haveYou
    price = Product.getPrice(self.price) + self.price
  File "C:\Users\Tanner Harmer\Desktop\Coffee2\CashBox.py", line 108, in select
    if self.cashBox.haveYou(self.credit) == True:
  File "C:\Users\Tanner Harmer\Desktop\Coffee2\CashBox.py", line 50, in oneAction
    Selector.select(self,int(words[1]))
  File "C:\Users\Tanner Harmer\Desktop\Coffee2\CashBox.py", line 122, in main
    while m.oneAction():
  File "C:\Users\Tanner Harmer\Desktop\Coffee2\CashBox.py", line 128, in <module>
    main()

或者如果在 hasYou 我使用

price = Product.getPrice  
return self.credit >= price

Exception has occurred: TypeError
'>=' not supported between instances of 'int' and 'function'
  File "C:\Users\Tanner Harmer\Desktop\Coffee2\CashBox.py", line 23, in haveYou
    return self.credit >= price
  File "C:\Users\Tanner Harmer\Desktop\Coffee2\CashBox.py", line 108, in select
    if self.cashBox.haveYou(self.credit) == True:
  File "C:\Users\Tanner Harmer\Desktop\Coffee2\CashBox.py", line 50, in oneAction
    Selector.select(self,int(words[1]))
  File "C:\Users\Tanner Harmer\Desktop\Coffee2\CashBox.py", line 122, in main
    while m.oneAction():
  File "C:\Users\Tanner Harmer\Desktop\Coffee2\CashBox.py", line 128, in <module>
    main()

Answer 1

您需要在末尾添加()才能实际获取值。

所以而不是：

price = Product.getPrice  
return self.credit >= price

利用：

price = Product(<Here put the 3 values that this class needs>).getPrice()  
return self.credit >= price

Answer 2

如果准确性是关键（在金融领域经常如此），则永远不要使用浮点数。 相反，我建议您将货币存储为以美分数表示的整数。

例如，如果某人的银行账户余额为 1,343.98 美元，那么您将其存储为 134,398 美分。 每当您将 object 转换为字符串时，它都会得到一个不错的小数点。

import math

class PecuniaryPurse:
    currency_codes = frozenset((
        "EUR", "USD", "GBP", "JPY", "CHF",
        "AUD", "CAD"
    ))

    @classmethod
    def to_int(cls, amount):
        if isinstance(amount, cls):
            _amount_int = amount._amount
        else:
            _amount_flt = float(str(amount))
            _amount_int = int(amount)
            if not math.isclose(amount, _amount_flt):
                raise ValueError()
        return _amount_int

    def __init__(self, currency_code, _amount = 0):
        try:
            assert (currency_code in self.currency_codes)
            self._currency_code = currency_code
            self._amount = type(self).to_int(_amount)
        finally:
            pass

    def __str__(self):
        return ''.join(str(x) for x in (
                self._currency_code,
                "  ",
                str(self._amount // 100),
                ".",
                str(self._amount % 100)
        ))

    def __add__(self, other):
        if isinstance(other, type(self)):
            assert(self._currency_code == other._currency_code)
            return type(self)(self._currency_code, self._amount + other._amount)
        else:
            other = type(self).to_int(other)
        return type(self)(self._currency_code, self._amount + other)

PP = PecuniaryPurse
p = PP("USD", 1234) + PP("USD", 99)
print(p) # USD  13.33

Answer 3

import time
import sys

class CashBox(object):
    def __init__(self):
        self.credit = 0
        self.totalReceived = 0
        #self.price = 35

    def deposit(self,amount):
        self.credit = amount + self.credit
        self.totalReceived = amount + self.totalReceived
        print(self.credit)
        print(type(self.credit))
        return self.credit

    def returnCoins(self):
        print("Returning ", self.credit/100, " dollars.")
        self.totalReceived = 0

    def haveYou(self,name,price,recipe):
        return self.credit >= price

    def deduct(self,amount):
        pass

    def totalCoins(self):
        return self.totalReceived

class CoffeeMachine(object): 

    def __init__(self):
        self.cashBox = CashBox()
        self.credit = CashBox.__init__
        self.selector = self.cashBox

    def oneAction(self):

        while True:
            command = input("""
            ______________________________________________________
            PRODUCT LIST: all 35 cents, except bouillon (25 cents)
            1=black, 2=white, 3=sweet, 4=sweet & white, 5=bouillon      
            Sample Commands: insert 25, select 1, cancel, quit.
            Your command: 
            """)
            words = command.lower().split()           
            if 'select' in words:
                Selector.select(self,int(words[1]))
            elif 'insert' in words:
                coinsAllowed = [5,10,25,50]
                if int(words[1]) in coinsAllowed:
                    self.cashBox.deposit(int(words[1]))
                else:
                    print("""
                    That is not one of the allowed coins, 
                    please insert a penny, nickel, dime, quarter,
                    or half-dollar. Thank you.
                    """)
            elif 'cancel' in words:
                print("Cancelling transaction. Returning to main menu: ")
                self.cashBox.returnCoins()
            elif 'quit' in words:
                print("Have a nice day!")
                break
            else:
                print("That is not an option")

    def totalCash(self):
        return self.cashBox.totalReceived    

class Product(object):

    def __init__(self,name,price,recipe):
        self.name = name
        self.price = price
        self.recipe = recipe

    def getPrice(self):
        return self.price

    def make(self):
        for item in self.recipe:
            print("dispensing", item)
            time.sleep(0.5)
        print("Enjoy your", self.name)
        time.sleep(0.5)
        print(self.price)

class Selector(object):

    def __init__(self):
        #self.Product = Product()
        self.cashBox = CashBox()
        self.credit = CashBox.deposit
        #self.products.append(Product.

    def select(self, choiceIndex):
        recipes = {
            1 : ["Black coffee",35,["cup", "coffee", "water"]],
            2 : ["White coffee",35,["cup", "coffee", "creamer", "water"]],
            3 : ["Sweet coffee",35,["cup", "coffee", "sugar", "water"]],
            4 : ["White & Sweet coffee",35,["cup", "coffee", "sugar", "creamer", "water"]],
            5 : ["Bouillon",25,["cup bouillonPowder", "water"]]
        }
        if choiceIndex in range(1,len(recipes)+1):
            self.choiceIndex = choiceIndex
            self.recipe = recipes.get(choiceIndex)
            product = Product(*self.recipe)
            if self.cashBox.haveYou(*self.recipe) == True:
                #print(self.recipe,"Great selection")
                #price = CashBox.haveYou(*self.recipe)
                product.make()              
            else:
                print("You don't have enough credit for that, please insert more money.")
        else:
            print("That selection does not exist")

def main():
    m = CoffeeMachine()
    while m.oneAction():
        pass
    total = m.totalCash()
    print(f"Total Cash: ${total/100:.2f}")

if __name__ == "__main__":
    main()