购物车程序

需求:

1. 启动程序后，让用户输入工资，然后打印商品列表
2. 允许用户根据商品编号购买商品
3. 用户选择商品后，检测余额是否够，够就直接扣款，不够就提醒 
4. 可随时退出，退出时，打印已购买商品和余额

提示：

1.enumeratie（）函数用法，用于遍历序列中的元素以及它们的下标

names=["a", 'b', 'c', 'd']
for i,ele in enumerate(names):
    print(i,ele)

0 a
1 b
2 c
3 d

2.列表的嵌套

products=[ ['a',1], ['b',2], ['c',3] ]
for i,ele in enumerate(products):
    print(i,ele[0],ele[1])

0 a 1
1 b 2
2 c 3

products = [
    ["Ipone",5800],
    ["Mac",15800],
    ["Coffee",30],
    ["Bike",2000],
    ["Cloth",500],
]
shopping_list = []


while True:
    salary = input("Your salary:")
    if salary.isdigit():
        salary = int(salary)
        break
    else:
        continue

while True:
    print("product list".center(50,"-"))
    for index,i in enumerate(products):
        print(index,".",i[0],i[1])
    choice = input("请输入商品编号[quit]>>:")
    if choice.isdigit():
        choice = int(choice)
        if choice >=0 and choice < len(products):
            #判读钱够不够
            p = products[choice]
            if salary >= p[1]:#买的起
                salary -= p[1] #扣钱
                shopping_list.append(p) #加入购物车
                print("Added 33[32;1m[%s]33[0m into your shopping cart,and your current balance is 33[41;1m%s33[0m" %(p[0],salary))
            else:
                print("钱不够，你只有[%s]" % salary)
        else:
            print("没有此商品...")
    elif choice == "quit":
        print("已购买商品".center(50,"-"))
        for i in shopping_list:
            print(i[0])
        print("Your left balance is ", salary)
        exit()