Question

我是python的新手，尝试制作while循环时遇到了麻烦。每当我运行代码时，无论有多少项目，它都会不断提示我输入。


print("what is your name")
name = input("")
print("hello " + name)
print("how many inventory items do you want to buy")
items = input()
while (items > 0):
         print("what is the inventory number of the item")
         inventoryNum = int(input())
         if (inventoryNum >= 1000 and inventoryNum <= 1999 ):
             print("the item is on the lower level")

         elif (inventoryNum == 8005 or inventoryNum == 8000):
             print("the item is on the mezzanine")

         elif (inventoryNum > 1999 and inventoryNum <= 5000 or inventoryNum > 9000):
             print("the item is on the main floor")

         elif (inventoryNum > 5000 and inventoryNum <= 9000 and inventoryNum != 8005 and inventoryNum != 8000):
             print("the item is on the upper level")
             items = items - 1

Answer 1

这只是一个缩进问题。支出您的items = items - 1，因为它位于您最后的elif语句中。

while (items > 0):
  print("what is the inventory number of the item")
  inventoryNum = int(input())
  if (inventoryNum >= 1000 and inventoryNum <= 1999 ):
      print("the item is on the lower level")

  elif (inventoryNum == 8005 or inventoryNum == 8000):
      print("the item is on the mezzanine")

  elif (inventoryNum > 1999 and inventoryNum <= 5000 or inventoryNum > 9000):
      print("the item is on the main floor")

  elif (inventoryNum > 5000 and inventoryNum <= 9000 and inventoryNum != 8005 and inventoryNum != 8000):
      print("the item is on the upper level")
  items = items - 1

Answer 2

查看下面的代码。您的代码主要存在两个问题，它们被注释了：

print("what is your name")
name = input("")
print("hello " + name)
print("how many inventory items do you want to buy")
items = int(input()) #You forgot to convert the input from str to int
while (items > 0):
    print("what is the inventory number of the item")
    inventoryNum = int(input())
    if (inventoryNum >= 1000 and inventoryNum <= 1999):
        print("the item is on the lower level")

    elif (inventoryNum == 8005 or inventoryNum == 8000):
        print("the item is on the mezzanine")

    elif (inventoryNum > 1999 and inventoryNum <= 5000 or inventoryNum > 9000):
        print("the item is on the main floor")

    elif (inventoryNum > 5000 and inventoryNum <= 9000 and inventoryNum != 8005 and inventoryNum != 8000):
        print("the item is on the upper level")
    #you put the code in the scope of elif; it should be in the scope of while loop.
    #the problem arised due to the indentation.
    items = items - 1

Answer 3

我看到了您的问题，并且注意到了几件事：

第一个问题是次要问题，但可以很快解决：

items = input()

这应该是：

items = int(input())

由于无论何时我们想从输入函数中获取一个值，无论您是否传递数字，我们都将获得一个字符串类型。为了解决这个问题，我们将一个int放在字符串前面使它成为一个整数

简化代码和缩进问题：

print("what is the inventory number of the item")
inventoryNum = int(input())

可以简化为：

inventoryNum = int(input("What is the inventory number of the item: "))

-此外，最后，由于似乎所有不属于与stockNum相关的前三个条件的项目都位于主楼层，因此您可以使用else语句。像这样：

if(inventoryNum >= 1000 and inventoryNum <= 1999):
        print("The item is on the lower level")
    elif(inventoryNum == 8005 or inventoryNum == 8000):
        print("The item is on the mezzanine")
    elif(inventoryNum > 1999 and inventoryNum <= 5000) or (inventoryNum>9000):
        print("The item is on the main floor")
    else:
        print("The item is on the upper level")

最后，为了使while循环起作用，必须在外部缩进项目值减1，否则，只有当elif语句之一是它所采用的路径时，值才减1：

   print("the item is on the upper level")
             items = items - 1

应该是：

    inventoryNum = int(input("What is the inventory number of the item: "))

    if(inventoryNum >= 1000 and inventoryNum <= 1999):
        print("The item is on the lower level")
    elif(inventoryNum == 8005 or inventoryNum == 8000):
        print("The item is on the mezzanine")
    elif(inventoryNum > 1999 and inventoryNum <= 5000) or (inventoryNum>9000):
        print("The item is on the main floor")
    else:
        print("The item is on the upper level")
    #items -= 1 is indented outside of the if/elif/else statement since you want the value of items to decrease after each iteration    
    items -= 1 #Simpler way of saying items = items - 1, works with + and / as well

print("All items registered. End of program") #Thought that this would be a nice way of notifying the user that they've reached the end of the program

希望这会有所帮助。

Answer 4

处理此问题的另一种方法是使函数询问您是否还要继续执行该程序，例如：

def Continue():
   answer = input("Do you want to continue? (Yes/No - Y/N)")
      if(answer == "Yes" or answer == "Y"):
         pass
      elif(answer == "No" or answer == "N"):
         print("Goodbye")
         sys.exit();

我注意到您的if语句没有任何终止点（例如在if < 1000中），因为每次您键入的值小于此间隔时，都应该反复键入，我对您的输入进行了一些修复（就像上面的一些伴侣所做的一样），并且当您的库存编号不在任何类别中时，您应该在最后输入else语句：

name = input("what is your name: ")
print("hello " + name)
items = int(input("how many inventory items do you want to buy: "))
while (items > 0):
         inventoryNum = int(input("what is the inventory number of the item: "))
         if (inventoryNum >= 1000 and inventoryNum <= 1999):
             print("the item is on the lower level")
             Continue()
         elif (inventoryNum > 1999 and inventoryNum <= 5000 or inventoryNum > 9000):
             print("the item is on the main floor")
             Continue()
         elif (inventoryNum == 8005 or inventoryNum == 8000):
             print("the item is on the mezzanine")
             Continue()
         elif (inventoryNum > 5000 and inventoryNum <= 9000 and inventoryNum != 8005 and inventoryNum != 8000):
             print("the item is on the upper level")
             Continue()
         else:
             print("item is not registered")
             Continue()
             items = items - 1

因此，每次您输入“是”时，它都会继续，相反，它将关闭应用程序

python中的while循环不会停止

4 个答案: