一个简单的购物车程序

　　前几天跟着视频做了一个简单的购物车程序，但是没有做出来，之后又跟着后面的视频，做了一个，视频里面老师也讲了，只有不断的尝试写，才能慢慢有感觉，越不写，越不会。下面是我前几天写的购物车和跟着视频做的购物车的对比：

　　自己写的：

__Author__ = "Zhang Peng"

salary = input("What is your monthly salary?\n")
somethings={"IPhone":5888,"杯子":8,"眼镜盒":15,"计算器":38,"鼠标":128,"电脑":7889,"零食":120,}
Shopping_Cart=[]

while True:
    dongxi = input("What do you want to buy? \n")

    if dongxi == 'quit':
        break

    elif somethings[dongxi] == 'KeyError':
        print("Sorry!The product you want is not found.")
        break

    elif salary - somethings[dongxi] >= 0:
        Shopping_Cart.append([dongxi,somethings[dongxi]],)
        salary = salary - somethings[dongxi]


    elif salary - somethings[dongxi] < 0:
        print("The balance you have left is not enough to buy it. Try something else, please.")
        print("Enter 'quit' to end the program.")




print(f'你还有{salary}块钱！')
print(f'Your shopping list:\n{Shopping_Cart}')

　　老师写的：

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 >=0:
                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")

 ​　　后面的视频布置的作业是把购物车进行优化，优化的内容是，分别添加用户和商家入口，用户可以显示自己以前的购物记录，已经钱包余额；商家可以添加商品和修改商品价格，下面代码是我自己研究研究写出来的，后面的保存和调用的方法还是不熟练，写的比较乱，试了好多遍，还是不行，大家可以看看：

product_list=[
    ('Iphone',5888),
    ('笔记本',12888),
    ('手表',10600),
    ('电视',3888),
    ('书',58),
]

id_list=["商家","用户","shangjia","yonghu"]
id_shopping=input("Please input your ID:\n")

exit_flag=False
        
if id_shopping=="shangjia":
    choice=input("你是否想添加\修改商品？添加商品输入'1'，修改商品输入'2',退出输入'q':\n")
    if choice=="1":
        while not exit_flag:
            name=input("请输入您想添加的商品名称：\n")
            name2=input("请输入您添加商品的价格：\n")
            if name=="q" or name2=="q":
                exit_flag=True
            else:
                product_list.append((name,name2),)

    elif choice=="2":
        while not exit_flag:
            name3=input("请输入您想修改价格的商品名称：\n")
            name4=input("请输入您想要修改的价格：\n")
                
            if name3=="q" or name4=="q":
                exit_flag=True  
            else:
                a=product_list.index(name3)
                product_list.remove(name3)
                product_list.index((name3,name4))

    else:
        if choice=="q":
            exit_flag=True
    print(product_list)


elif id_shopping=="yonghu":
    shopping_list=[]
    with open("shopping_list.txt") as f:
        print("你的购物车里已经有：\n")
        f.read()
    with open("salary.txt") as f:
        salary=f.read()
        print(salary)
    if salary.isdigit():    #isdigit 是判断输入的是不是一个数字
        salary=int(salary)
        while True:
            print("我们有一下商品：\n")
            for index,item in enumerate(product_list):
                print(index,item)
            user_choice=input("请问你还想买什么？:\n")
            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]
                    if p_item[1]<salary:  #买不起
                        shopping_list.append(p_item)
                        salary -=p_item[1]
                        print("您买的商品已经加入购物车")
                    else:
                        print("没钱别嘚瑟了")
                else:
                    print("没有您要的商品")
            elif user_choice == 'q':
                print("----------shopping list----------")
                for p in shopping_list:
                    print(p)
                    with open("shopping_list.txt","w") as f:
                        f.write("shopping_list")
                print("你还剩余",salary)
                salary.save("salary.txt")
                

            else:
                print("输入错误")

else:
    shopping_list=[]
    salary=input("请输入你的月薪：\n")
    if salary.isdigit():    #isdigit 是判断输入的是不是一个数字
        salary=int(salary)
        while True:
            for index,item in enumerate(product_list):
                print(index,item)
            user_choice=input("请问你想买什么？:\n")
            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]
                    if p_item[1]<salary:  #买不起
                        shopping_list.append(p_item)
                        salary -=p_item[1]
                        print("您买的商品已经加入购物车")
                    else:
                        print("没钱别嘚瑟了")
                else:
                    print("没有您要的商品")
            elif user_choice == 'q':
                print("----------shopping list----------")
                for p in shopping_list:
                    print(p)
                shopping_list.save("shopping_list.txt")
                print("你还剩余",salary)
                with open("salary.txt","w") as f:
                    f.write("salary")
                    exit()

            else:
                print("输入错误")

　　有兴趣的可以看一下，欢迎踊跃参与。给我写建议，谢谢！