简单的购物车程序

简单的购物车程序，用于练习，需求如下：

启动程序后，让用户输入工资，然后打印商品列表
允许用户根据商品编号购买商品
用户选择商品后，检测余额是否够，够就直接扣款，不够就提醒
可随时退出，退出时，打印已购买商品和余额

 1 #!/usr/bin/env python
 2 #-*- coding:utf-8 -*-
 3 # @Time    : 2017/9/14 16:46
 4 # @Author  : lichuan
 5 # @File    : shop_car.py
 6 
 7 product_list={
 8     "lenove":3000,
 9     "ASUS":4500,
10     "MSI":2800,
11     "HP":4200
12 }
13 FLAG_TAG=True
14 count=0
15 shop_car = {}  # 已购物的商品
16 shop_list = []  # 购物车列表
17 
18 while FLAG_TAG:
19     salary=input("input 'q' to exit,please input your salary:")
20     if salary == 'q':
21         FLAG_TAG=False
22     elif salary.isdigit():
23         salary=int(salary)
24     else:
25         print("input wrong,try again!")
26         continue
27     for p in product_list:
28         print("%d,%s  %d" % (count, p, product_list[p]))
29         shop_list.append(p)
30         count += 1
31 
32     while FLAG_TAG:
33         product_num=input("input 'q' to exit,please input the product no:")
34         if product_num == 'q':
35             FLAG_TAG=False
36         elif product_num.isdigit() and int(product_num) < count:
37             product_num=int(product_num)
38             if salary >= product_list[shop_list[product_num]]:
39                 if not shop_list[product_num] in shop_car:
40                     shop_car[shop_list[product_num]]=1
41                 else:
42                     shop_car[shop_list[product_num]]+=1
43                 salary = salary - product_list[shop_list[product_num]]
44             else:
45                 print("余额不足：请选别的商品！")
46                 continue
47         else:
48             print("input 'q' to exit or input a number!")
49             continue
50         print("你购买的商品如下：")
51         for s in shop_car:
52             print("%s: %d" %(s,shop_car[s]))
53         print("余额： %d" % salary)