python---购物车---更新

购物车程序更新：

更新商家入口，实现以下功能：

1. 商家能够修改商品价格；

2. 商家能够下线商品；

3. 商家能够增加商品；

4. 商品信息存在文件中

# -*- coding:utf-8 -*-
# LC
product_list = []
product_line = []
count = 0

with open("product_list","r") as f:                     #打开商家货品清单文件
    for item in f:
        product_line = item.rstrip().split(",")            #将每行赋值给成一个列表，以“，”区分
        product_list.append(product_line)                   #将每行的列表加入product_list列表中

print("This is your production".center(50,"-"))         #打印列表
for i in product_list:
    print(count,i)
    count+=1

#提供增加商品，修改商品价格，删除商品功能
while True:
    select = input("Please input you selection,'a' to add,'m' to modified the price,'d' to Delete,'q' to quit :")
    count = 0
    if select == 'a':
        add_product = input("Please input new product name:")
        add_price = input("Please input new product price:")
        new_product = [add_product,add_price]                       #将新添加的商品赋值成列表
        product_list.append(new_product)                            #向产品清单列表中插入新添加的商品
        with open("product_list","a") as f_add:                 #将添加的商品写入文件中，以追加的方式
            f_add.writelines(product_list[-1][0]+","+product_list[-1][1]+"
")
        print("33[1;31mThis is your new production list33[0m".center(50,"-"))
        for i in product_list:       #打印新的产品清单
            print(count,i)
            count+=1
    elif select == 'm':
        modify_index = input("Please input index of the item which you want to modify:")    #输入要修改价格的产品序号
        modify_index = int(modify_index)
        length = product_list.index(product_list[-1])   #判断输入的修改价格产品序号是否再产品清单范围
        if 0 <= modify_index <= length:
            new_price = input("Please input the new price:")                    #输入新的价格
            product_list[modify_index][1]=new_price                                 #将新的价格修改至产品清单列表中
            with open("product_list","w") as f_modify:                          #想修改的产品清单列表写入文件中
                for i in product_list:
                    f_modify.writelines(i[0]+","+i[1]+"
")
            print("33[1;31mThis is your new production list33[0m".center(50,"-"))
            for i in product_list:                                        #打印新的产品清
                print(count,i)
                count+=1
        else:
            print("Your select is invalid, Please try again!")      #如果输入的序号不在范围内，则报错重新来
    elif select == 'd':                                             #删除商品
        delete_index = input("Please input index of the item which you want to delete:")
        delete_index = int(delete_index)
        length = product_list.index(product_list[-1])               #判断输入的删除序号是否再产品清单范围
        if 0 <= delete_index <= length:
            product_list.pop(delete_index)                      #从产品清单中删除制定的产品
            with open("product_list","w") as f_del:
                for i in product_list:
                    f_del.writelines(i[0]+","+i[1]+"
")           #将新的产品清单写入文件中
            print("33[1;31mThis is your new production list33[0m".center(50,"-"))
            for i in product_list:
                print(count,i)
                count+=1
        else:
            print("Your select is invalid, Please try again!")

    elif select == "q":
        print("You have been quit!")
        break
    else:
        print("invalid input,please input again!")

pic,2
rice,3
water,32
phone,5000
pia,300

更新用户购买程序，实现以下功能：

1. 用户第一次购买输入薪资；

2. 用户购买商品信息写入文件；

3. 用户再次购买先读取之前的购买清单文件，查看余额；

# -*- coding:utf-8 -*-
# LC
import os
product_list = []           #定义商品清单列表
product_line = []           #定义商品清单中每行的列表
user_buy_list = []          #定义用户已经购买商品列表
user_buy_product = []       #定义用户购买单个商品的列表
with open("product_list","r") as f_production:              #读取商品清单列表
    for item_production in f_production:
        product_line = item_production.rstrip().split(",")
        product_list.append(product_line)

if os.path.getsize("shopping_list") == 0:                       #判断是否为第一次消费，如果消费清单文件为空，则第一次消费
    salary = input("Please input your salary:")
    balance = int(salary)                                           #将余额定义为薪资
else:
    length = len(open("shopping_list","rU").readlines())            #如果不是第一次消费，计算消费清单文件行数，提取消费列表
    count = 0
    with open("shopping_list", "r") as f_shopping_list:
        for shopping_item in f_shopping_list:
            count +=1
            if 2 <= count <= length-2:                          #去除第一行和最后两行，将消费清单中已购买的商品提取出来
                shopping_item = shopping_item.strip().split()   #将购买的商品转换为列表，包含商品，单价，数量
                user_buy_list.append(shopping_item)             #将已经购买的商品记录至用户消费清单列表中
            elif count == length:
                shopping_item = shopping_item.strip().split()
                balance = int(shopping_item[-1])                #如果非第一次消费，则余额为消费清单文件中的余额，提取出来
while True:
    print("This is the production list".center(50, "-"))
    count = 0
    for i in product_list:
        print(count, i)
        count += 1
    user_select = input("Your balance is %d, 's' to start to shopping,'q' to quit : "%(balance))
    if user_select == 's':
        user_buy_product = []
        user_select_index = input("Please select the index of the one you want to buy:")        #输入要购买的商品
        user_select_count = input("Please input the number how many you want to buy:")          #输入要购买的商品数量
        user_select_index = int(user_select_index)
        user_select_count = int(user_select_count)
        unit_price = int(product_list[user_select_index][1])                        #要购买的商品单价
        product_price = unit_price * user_select_count                              #购买的商品金额，即单价乘以总价
        if product_price <= balance:
            user_buy_product.append(product_list[user_select_index][0])             #将购买的商品的名称插入新的单个列表中
            user_buy_product.append(product_list[user_select_index][1])             #将购买的商品的单价插入新的单个列表中
            user_buy_product.append(str(user_select_count))                         #将购买的商品的数量插入新的单个列表中
            user_buy_list.append(user_buy_product)                                  #将新购买的商品，包含名称，单价，数量插入用户购买清单中
            balance = balance - product_price                                        #将金额出去已经购买的商品金额，以免余额不足
        else:                                                                       #购买的商品和数量，余额不足
            print("33[1;31mYour choice is out of your money!33[0m")
            continue
    elif user_select == 'q':
        break
    else:
        print("invalid input ,try again")
        continue

#统计用户购买商品的总金额和消费余额
total_price = 0
for i in user_buy_list:
    user_buy_product_price = int(i[1]) * int(i[2])          #用户购买的单个商品的总额，即单件商品的单价乘以数量
    total_price = total_price + user_buy_product_price      #统计消费总金额
total_consumption = ["Total_Consumption:"]
balance_list = ["Your balance:"]                            #消费清单上记录余额信息
balance_list.append(balance)
total_consumption.append(total_price)
user_buy_list.append(total_consumption)                     #将总消费金额信息插入用户消费清单中
user_buy_list.append(balance_list)                          #将余额信息插入用户消费清单中

#将用户购买的商品写入消费清单文件中，并记录总价和余额
with open("shopping_list","w") as f_buy:
    f_buy.writelines("product".center(15,"-")+"price".center(15,"-")+"count".center(15,"-")+"
")
    for i in user_buy_list:
        if len(i) == 3:                     #将商品写入
            f_buy.writelines(str(i[0]).center(15," ")+str(i[1]).center(15," ")+str(i[2]).center(15," ")+"
")
        else:                               #将余额和消费总额写入
            f_buy.writelines(str(i[0]).ljust(30, " ") + str(i[1]).center(15, " ") + "
")

#打印最终购买清单
print("This is your purchase list".center(45,"-"))
with open("shopping_list","r") as f_read:
    for i in f_read:
        print(i.strip("
"))

购买清单文件

----product---------price----------count-----
      pic             2              20      
      rice            3              50      
     water            32            300      
     phone           5000            2       
      pia            300             50      
     phone           5000            2       
     phone           5000            1       
Total_Consumption:                 49790     
Your balance:                       210