前幾天跟著視頻做了一個簡單的購物車程序，但是沒有做出來，之後又跟著後面的視頻，做了一個，視頻裏面老師也講了，只有不斷的嘗試寫，才能慢慢有感覺，越不寫，越不會。下面是我前幾天寫的購物車和跟著視頻做的購物車的對比：

　　自己寫的：

 1 __Author__ = "Zhang Peng"
 2 
 3 salary = input("What is your monthly salary?\n")
 4 somethings={"IPhone":5888,"杯子":8,"眼鏡盒":15,"計算器":38,"鼠標":128,"電腦":7889,"零食":120,}
 5 Shopping_Cart=[]
 
 6 
 7 while True:
 8     dongxi = input("What do you want to buy? \n")
 9 
10     if dongxi == ‘quit‘:
11         break
12 
13     elif somethings[dongxi] == ‘KeyError‘:
14         print("Sorry!The product you want is not found.")
15         break
16 
17     elif salary - somethings[dongxi] >= 0:
 
18         Shopping_Cart.append([dongxi,somethings[dongxi]],)
19         salary = salary - somethings[dongxi]
20 
21 
22     elif salary - somethings[dongxi] < 0:
23         print("The balance you have left is not enough to buy it. Try something else, please.")
24         print("Enter ‘quit‘ to end the program.
 
")
25 
26 
27 
28 
29 print(f‘你還有{salary}塊錢！‘)
30 print(f‘Your shopping list:\n{Shopping_Cart}‘)

　　老師寫的：

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("選擇要買嘛？>>>:")
        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: #買的起
                    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你的余額只剩[%s]啦，還買個毛線\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")

?　　後面的視頻布置的作業是把購物車進行優化，優化的內容是，分別添加用戶和商家入口，用戶可以顯示自己以前的購物記錄，已經錢包余額；商家可以添加商品和修改商品價格，下面代碼是我自己研究研究寫出來的，後面的保存和調用的方法還是不熟練，寫的比較亂，試了好多遍，還是不行，大家可以看看：

product_list=[
    (‘Iphone‘,5888),
    (‘筆記本‘,12888),
    (‘手表‘,10600),
    (‘電視‘,3888),
    (‘書‘,58),
]

id_list=["商家","用戶","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？添加商品輸入‘1‘，修改商品輸入‘2‘,退出輸入‘q‘:\n")
    if choice=="1":
        while not exit_flag:
            name=input("請輸入您想添加的商品名稱：\n")
            name2=input("請輸入您添加商品的價格：\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("請輸入您想修改價格的商品名稱：\n")
            name4=input("請輸入您想要修改的價格：\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("你的購物車裏已經有：\n")
        f.read()
    with open("salary.txt") as f:
        salary=f.read()
        print(salary)
    if salary.isdigit():    #isdigit 是判斷輸入的是不是一個數字
        salary=int(salary)
        while True:
            print("我們有一下商品：\n")
            for index,item in enumerate(product_list):
                print(index,item)
            user_choice=input("請問你還想買什麽？:\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:  #買不起
                        shopping_list.append(p_item)
                        salary -=p_item[1]
                        print("您買的商品已經加入購物車")
                    else:
                        print("沒錢別嘚瑟了")
                else:
                    print("沒有您要的商品")
            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("你還剩余",salary)
                salary.save("salary.txt")
                

            else:
                print("輸入錯誤")

else:
    shopping_list=[]
    salary=input("請輸入你的月薪：\n")
    if salary.isdigit():    #isdigit 是判斷輸入的是不是一個數字
        salary=int(salary)
        while True:
            for index,item in enumerate(product_list):
                print(index,item)
            user_choice=input("請問你想買什麽？:\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:  #買不起
                        shopping_list.append(p_item)
                        salary -=p_item[1]
                        print("您買的商品已經加入購物車")
                    else:
                        print("沒錢別嘚瑟了")
                else:
                    print("沒有您要的商品")
            elif user_choice == ‘q‘:
                print("----------shopping list----------")
                for p in shopping_list:
                    print(p)
                shopping_list.save("shopping_list.txt")
                print("你還剩余",salary)
                with open("salary.txt","w") as f:
                    f.write("salary")
                    exit()

            else:
                print("輸入錯誤")

　　有興趣的可以看一下，歡迎踴躍參與。給我寫建議，謝謝！

一個簡單的購物車程序