从嵌套列表中减去一个整数答案

【问题标题】：Subtracting an integer from nested list从嵌套列表中减去一个整数
【发布时间】：2020-12-21 14:13:06
【问题描述】：

• 如果有足够的糖果出售，系统必须从数量 [项目 2] 中减去输入的金额，以便显示商店中剩余的糖果数量） • 如果没有足够的糖果出售（客户想要购买的糖果多于可用的糖果），系统必须通知用户无法进行交易。需要在 def 函数中完成，任何人都可以帮助解决这个问题！

lst_s = [
["Smarties", 5, 37], ["Cookie", 8, 80], ["Fizzies", 4, 50], ["Chocolate bar", 4, 25]
]

def update_quantity():
    name = str(input("Enter name of confectionary: "))
    price = str(input("Enter price: "))
    amount = int(input("enter quantity customer wants to buy"))

    for i in range(len(lst_s)):
        item = lst_s[i]
        iamount = item[2]
        if amount > iamount:
            print("Sorry not enough in store to sell")
        else:
            iamount = iamount - amount
            print(lst_s)

如果我输入名称为 Cookie，价格为 8，数量为 3，则所需的输出将是：

["Smarties", 5, 37], ["Cookie", 8, 77], ["Fizzies", 4, 50], ["Chocolate bar", 4, 25]

因为原来的 Cookie 数量已经减去了 3 个

【问题讨论】：

标签： python list nested-lists calculation python-3.9

【解决方案1】：

试试这个：

def update_quantity():
  name = str(input("Enter name of confectionary: "))
  price = str(input("Enter price: "))
  amount = int(input("enter quantity customer wants to buy"))

  for i in range(len(lst_s)):
    item = lst_s[i]
    item_name = item[0]
    iamount = item[2]
    if name != item_name:
        continue
    if amount > iamount:
        print("Sorry not enough in store to sell")
    else:
        lst_s[i][2] = iamount - amount
        print(lst_s)

【讨论】：

【解决方案2】：

应该相对简单。您可能想使用 dict 来存储产品。

lst_s = [
  ["Smarties", 5, 37],
  ["Cookie", 8, 80],
  ["Fizzies", 4, 50],
  ["Chocolate bar", 4, 25],
]

def update_quantity():
    name = str(input("Enter name of confectionary: "))
    price = str(input("Enter price: "))
    amount = int(input("enter quantity customer wants to buy"))

    for product in lst_s:
        if product[0] == name:
            if amount > product[2] :
                print("Sorry not enough in store to sell")
            else:
                product[2] = product[2] - amount
            break;
    print(lst_s)
    
update_quantity();

【讨论】：