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]+"\n")
         print("\033[1;31mThis is your new production list\033[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]+"\n")
             print("\033[1;31mThis is your new production list\033[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]+"\n")           #将新的产品清单写入文件中
             print("\033[1;31mThis is your new production list\033[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!")

商家入口程序

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

货品清单文件

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("\033[1;31mYour choice is out of your money!\033[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,"-")+"\n")
     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," ")+"\n")
         else:                               #将余额和消费总额写入
             f_buy.writelines(str(i[0]).ljust(30, " ") + str(i[1]).center(15, " ") + "\n")

 #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("\n"))

用户端程序

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      

购买清单文件