python练习_购物车（简版）
需求：
- 写一个python购物车可以输入用户初始化金额
- 可以打印商品，且用户输入编号，即可购买商品
- 购物时计算用户余额，是否可以购买物品
- 退出结算时打印购物小票
以下代码实现的功能与思路：
功能：
（1）预算金额控制，只能输入大于0的数字
（2）商品格式化打印 （3）选择完成要买的商品后，提示用户再次确认，确认后开始计算用户余额是否大于等于商品价格，价格正确后则加入购物车 （4）输入q则进行结算，结算时将重复的商品进行合并，显示个数，并计算消费总额和余额思路：
（1）商品打印通过嵌套列表实现
（2）购买商品是只需要比较用户余额和商品价格即可，如果比商品金额打就把这个商品加入到一个列表中
（3）结算时计算用户购物车列表即可
流程图：
使用方法：
执行环境：Python3.5
执行方法，执行执行即可
代码：
1 #!/usr/bin/env python 2 # -*- coding: utf-8 -*- 3 4 import time 5 6 List_items = [ ["iPhone4",100],["iPhone5",200],["iPhone6",300],["iPhone7",4000],["Python",10000],] 7 User_shopping_cart = [] 8 9 def in_money():10 '''11 判断用户输入金额的函数12 '''13 global user_in_money14 while True:15 user_in_money = input("Please enter initial funds:").strip()16 if user_in_money.isdigit():17 if int(user_in_money) > 0:18 while True:19 print_lists()20 else:21 print("\033[31mInput Error!\033[0m")22 else:23 print("\033[31mInput Error!\033[0m")24 25 def print_lists():26 '''27 获取用户输入的编号，调用结算模块28 :return:29 '''30 print("Product List".center(40,"-"))31 Spaces = " "*232 for Product_info in List_items:33 Underlined = 20-len(Product_info[0])34 print(Spaces,List_items.index(Product_info)+1,Spaces,Product_info[0],"."*Underlined,Product_info[1])35 print("-"*40)36 37 in_Numbering = input("Please enter the product number,[q]exit billing:").strip()38 if in_Numbering.isdigit():39 if int(in_Numbering) > 0 and int(in_Numbering)<= len(List_items):40 Transaction_Calculations(in_Numbering)41 else:42 print("\033[31mThe item number does not exist!\033[0m")43 else:44 if in_Numbering == "q":45 settlement()46 else:47 print("\033[31mInput Error!\033[0m")48 49 def Transaction_Calculations(Numbering):50 '''51 加入购物车模块，判断用户余额是否足够购买商品52 '''53 global user_in_money54 user_in_money = int(user_in_money)55 Numbering = int(Numbering)56 Pu_confirmation = input("Product \033[32m%s\033[0m Whether to add to cart(y/n):"%List_items[Numbering-1][0]).strip()57 if Pu_confirmation == "y":58 if user_in_money >= List_items[Numbering-1][1]:59 User_shopping_cart.append(List_items[Numbering-1])60 user_in_money = user_in_money - List_items[Numbering-1][1]61 print("Product %s Added Cart, Current Balance %s¥"%( List_items[Numbering-1][0],user_in_money))62 else:63 print("The balance is insufficient, the commodity price \033[31m%s\033[0m￥,lacks \033[31m%s\033[0m￥"%(List_items[Numbering-1][1],List_items[Numbering-1][1]-user_in_money))64 else:65 print("\033[31mNot added to cart\033[0m")66 67 def settlement():68 '''69 结算模块70 '''71 if len(User_shopping_cart) == 0:72 print("Shopping Cart There are no products, thank you patronage goodbye")73 exit()74 else:75 print("Shopping list".center(50,"-"))76 consumption = 077 new_user = []78 [new_user.append(i) for i in User_shopping_cart if not i in new_user]79 for user_cart in new_user:80 number = User_shopping_cart.count(user_cart)81 settlement_un = 15-len(user_cart[0])82 to_settlement_un = 25 - settlement_un - len(str(user_cart[1])) - len(user_cart[0])83 consumption += user_cart[1]*number84 print(" "*5,user_cart[0],"."*settlement_un,user_cart[1],"￥","."*to_settlement_un,"%s个"%(number))85 times = time.strftime("%Y-%m-%d %H:%M:%S",time.localtime(time.time()))86 print(times.center(50,"-"))87 print("Shopping cost \033[32m%s\033[0m¥, Current balance \033[32m%s\033[0m¥,Thank you to patronize!".center(50,"-")%(consumption,user_in_money))88 exit()89 90 if __name__ == "__main__":91 in_money()