product_list = [
        (‘iphone‘, 5800),
        (‘mac pro‘, 9800),
        (‘bike‘, 800),
        (‘watch‘, 10600),
        (‘coffee‘, 31),
        (‘alex python‘, 120)
        ]
shopping_list = []
salary = input(‘input your salary: ‘)

if salary.isdigit():
    salary = int(salary)
    while True:
        for index, item in enumerate(product_list):
            #print(product_list.index(item), item)
            print(index, item)
        user_choice = input(‘选择要买嘛>>: ‘)
        if user_choice.isdigit():
            user_choice = int(user_choice)
            if user_choice < len(product_list) and user_choice > -1:
                p_item = product_list[user_choice]
                if p_item[1] <= salary: #买的起
                    shopping_list.append(p_item)
                    salary -= p_item[1]
                    print(‘Added %s into shopping cart, your current balance is \033[31;1m%s\033[0m‘ %(p_item, salary))
                else:
                    print(‘\033[41;1m你的余额只剩[%s]啦，还买个毛线\033[0m‘ % salary)
            else:
                print(‘product code [%s] is not exist!‘ % user_choice)
        elif user_choice == ‘q‘:
            print(‘------shopping list-------‘)
            for p in shopping_list:
                print(p)
            print(‘Your current balance:‘, salary)
            exit()
        else:
            print(‘invalid option‘)