python 列表应用-简单的购物车

# -*- coding=utf-8 -*-
# Author:gx
#购物车

product_list = [
    ("Iphone",5800),
    ("Mac Pro",10800),
    ("Bike",800),
    ("Watch",12000),
    ("Alex Python",50),
    ("Coffee",30)
]

shopping_list = []

salary = input("Input your salary:") #输入工资
if salary.isdigit():   #判断输入的工资是不是数字
    salary = int(salary) #是数字转成int型
    while True:
        for item in product_list :
            print(product_list.index(item),item) #打印出商品下标及商品名称及价格
        use_choice = input("请选择你要买的商品编号--->:")
        if use_choice.isdigit(): #判断输入的是否数字
            use_choice = int(use_choice) #转int
            if use_choice < len(product_list) and use_choice >= 0: #判断输入的商品编号是否在范围内
                p_item = product_list[use_choice]
                if p_item[1] <= salary: #买的起
                    shopping_list.append(p_item) #加入购物车列表
                    salary = salary - p_item[1] #计算余额
                    print("Added %s into shopping cart,your current balance is 33[31;1m%s33[0m" %(p_item,salary)) #打印余额
                else: #买不起
                    print("33[41;1m你的余额仅剩[%s]33[0m" % salary) #打印余额
            else: #不在已有的商品列表中
                print("product code %s is not exist",use_choice) #提示不存在
        elif use_choice =='q': #判断输入q退出
            print("------shopping list--------") 
            for p in shopping_list:
                print(p) #循环打印出购买的商品列表
            print("your current balance:",salary) #打印余额
            exit() #退出
        else: #判读输入的既不是数字，也不是q
            print("invalid option")
else:
    print("please input int salary ")