购物车程序练习

#需求：1.启动程序以后，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，检查余额是否够，够就直接扣款，不够就提醒
#      4.可随时推出，推出时，打印已购买的商品和余额。
product_list=[('iphone',5800),
              ('mac book',9800),
              ('bike',800),
              ('watch',10600),
              ('coffee',31),
              ('book',120),]
shopping_list=[]
salary=input('input your salary:')
if salary.isdigit():
    salary=int(salary)
    while True:
        for i in product_list:#循环打印列表!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
            print(product_list.index(i),i)#通过下标打印商品编号
    #      while True:
    #       for index,item in enumerate(product_list):#方法二enumerate（枚举，计算，列举）:
     #          print(index,item)
        user_choice=input('what you want to buy')
        if user_choice.isdigit():
            user_choice=int(user_choice)
            if user_choice<len(product_list) and user_choice>=0:
                p_item=product_list[user_choice]#product_list[user_choice]里面有商品和价格，取价格
                if p_item[1]<=salary:
                    shopping_list.append(p_item)#将所买物品p_item追加到shoppinglist
                    salary-=p_item[1]
                    print('Added %s into shopping cart,your current balence is \033[31;1m%s\033[0m'%(p_item,salary))
                else:
                    print('\033[41;1myour balance  is only[%s]\033[0m'%salary)
        elif user_choice=='q':
            print('exit------------')
            print('--------------------shopping list----------------------------')
            for p in shopping_list:
                print(p)
            print('your current balance:',salary)
            exit()
        else:
            print('invalid option')