如何使python食物计算器保持一致？

Question

while 1:
    pie = 50
    pieR = pie
    pieRem = pieR - buy
    print("We have ", pieRem, "pie(s) left!")
    buy = int(input("How many pies would you like?  "))
    pieCost = 5
    Pie = pieCost * buy
    if buy == 1:
        print(pieCost)
        pieS = pieR - buy
    elif buy > 1:
        print(Pie * 0.75)
    else:
        print("Please enter how many pies you would like!")

当我打开控制台时，它会询问我想买多少个馅饼，然后我把剩下的馅饼数量显示出来，但是馅饼的价值每次都会刷新。所以如果我第一次选择要2个馅饼，它会说我们还剩48个馅饼（默认馅饼值是50），然后在它第二次询问我，我输入3，而不是下降到45，它会刷新并下降到47个。在

我希望我能解释清楚，我希望有人知道如何解决这个问题，谢谢。在

Answer 1

如果你使用类和对象，你就不需要全局变量了，你可以很容易地将代码扩展到其他产品（例如：牛角面包、百吉饼、汤、咖啡、三明治等等）在

class pies:
""" Object To Sell Pies """

def __init__(self):
    """ Constructor And Initialise Attributes """       
    self.pies=50
    self.amount = 0     
    self.cost = 5

def buy(self,buy):
    """ Method To Buy Pies """       

    if (buy > self.pies):
        print "Sorry Only %d Pies in Stock" % self.pies
    elif (self.pies >= 1):
        self.pies =self.pies - buy
        print "Cost is : %.02f" % ( 0.75 * buy )
        print "We have %d and pies in stock" % (self.pies) 
    elif (self.pies == 1):
        self.pies =self.pies - buy
        print "Cost is : %.02f" % ( self.cost * buy )
        print "We have %d pies in stock now" % (self.pies) 

    else:
        print "Sorry Pies Out of Stock !"  
        self.buy = 0
        self.pies = 0

将上面的代码另存为pieobject.py那就叫它：

^{pr2}$

Answer 2

每次代码循环回到开头，pie就会被重新定义为50。您需要在while循环之外定义变量pie：

pie = 50
while 1:
    ...

---

抱歉，但是你的代码一团糟，尤其是变量名。我帮你清理了一下：

^{pr2}$

Answer 3

从下面的@Haidros代码

buy,pies,cost = 0,50,5
while 1:
    if pies<1:
        print ('Sorry no pies left' )
        break
    print("We have ", pies, "pie(s) left!")
    buy = int(input("How many pies would you like?  "))
    if pies-buy<0:buy = int(input("Only %s pies remaining How many pies would you like?"%pies))                  
    if buy>0:
        if buy==1:print(cost*buy)
        else:print(cost*buy * 0.75)
        pies-=buy       
    else:
        print("Please enter how many pies you would like!")