一个简单的购物车例子练习

 1 #coding:utf-8
 2 
 3 '''
 4 购物车：
 5 显示商品和购买价格。
 6 购入商品，加入购物车。
 7 付款，余额不足时提示，并可重新购买。
 8 '''
 9 
10 shop_cart = []
11 amount = 0
12 wallet = 100
13 commodity = {"大米":60,"香蕉":8,"饼干":12,"榴莲":17}
14 
15 print("商品名称:	金额(元):")
16 for k,v in commodity.items():
17     print("%s		%s"%(k,v))
18 
19 while True:
20     print("
结账请输入[B]，重新购买请输入[R]，退出请输入[Q]")
21     shop = input("请输入购买商品名称:")
22     if isinstance(shop,str):
23         if shop == "Q":
24             print("
Goodbye Baby!!")
25             break
26         if shop == "R":
27             print("
I am back. baby!!")
28             continue
29         elif shop == "B":
30             for i in shop_cart:
31                 amount += commodity[i]
32             if wallet < amount:
33                 print("
余额不足！！
供需付款 %s (元)，
剩余金额 %s (元)"%(amount,wallet))
34             else:
35                 wallet -= amount
36                 for i in shop_cart:
37                     print("%s %s (元)" % (i, commodity[i]))
38                 print("=================
账单：%s (元)"%amount)
39                 print("余额 %s (元)"%wallet)
40         elif shop in commodity.keys():
41             shop_cart.append(shop)
42             print("
购物车：")
43             for n in shop_cart:
44                 print("----------
%s	%s (元)"%(n,commodity[n]))
45         else:
46             print("
输入有误，请输入需要购买商品的名称！！！
")
47     else:
48         print("
输入有误，请输入需要购买商品的名称！！！
")