python入门之实例-购买商品

需求：

　　选择商品，结算所选的商品

#目前总资产
asset_all = 0
#所选商品总价
all_price = 0
#购物车列表，目前已选择商品
#每个元素的结构："商品名":{'price':"单个商品价格",'num':"购买数量"}
car_dict = {}

i1 = input("请输入总资产：")
asset_all += int(i1)

goods = [
    {"name":"电脑","price":1999},
    {"name":"鼠标","price":50},
    {"name":"键盘","price":40},
    {"name":"U盘","price":20}
]
#循环输出商品信息
for k,i in enumerate(goods,1):
    print(k,i['name'],i['price'])

#选择商品将其加入购物车
while True:
    i2 = input("请选择商品(q结算)：")
    if i2.lower() == 'q':
        break
    i2 -= 1
    name = goods[i2]["name"]
    price = goods[i2]["price"]
    if name in car_dict.keys():
        car_dict[name]["num"] += 1
    else:
        car_dict[name] = {"price":price,"num":1}

#计算购物车里所有商品的总价格
for i,j in car_dict.items():
    p = j["price"]
    n = j["num"]
    all_sum = p * n
    all_price += all_sum

#判断是否能购买商品
if all_price > asset_all:
    print("余额不足，请充值")
else:
    asset_all -= all_price
    print("购买成功")
    car_dict.clear()