Python实现购物车功能的方法分析

本文实例讲述了Python实现购物车功能的方法。分享给大家供大家参考，具体如下：1、程序

本文实例讲述了Python实现购物车功能的方法。分享给大家供大家参考，具体如下：

1、程序的源代码如下：

salary = input('input your salary:')
if salary.isdigit:
 salary = int(salary)
else:
 exit('salary is not digit!!')
welcome_msg = 'welcome to our shoping mall'
print(welcome_msg.center(50,'-'))
product_list = [
 ('Iphone',5888),
 ('Mac Air',8000),
 ('XiaoMi',19.9),
 ('coffee',30),
 ('Tesla',820000),
 ('Bike',700),
 ('Cloth',200)
]
shop_car = []
#推出标志位
exit_flag = 0
while exit_flag is not True:
 print('product list :'.center(50,'-'))
 for item in enumerate(product_list):
 index = item[0] #获得商品序号
 p_name = item[1][0] #获得商品名称
 p_price= item[1][1] #获得商品价格
 print(index,p_name,p_price)
 user_choice = input('[q=quit,c=check] what do you want to buy?:')
 if user_choice.isdigit():
 user_choice = int(user_choice)
 if user_choice < len(product_list): #输入的商品序号要在范围之内
 p_item = product_list[user_choice] #选择的商品
 if p_item[1] <= salary: #买得起
 shop_car.append(p_item) #放入购物车
 salary -= p_item[1] #减钱
 print('purchased products are:'.center(40, '-'))
 for item in shop_car:
 print(item)
 print('Your balance is [%s]' % salary)
 else: #买不起
 print('Your balance is [%s],cannot buy the product!'%salary)
 else:
 print('we do not have the product,please input again!')
 elif user_choice == 'q' or user_choice == 'quit':
 print('purchased products are:'.center(40,'-'))
 for item in shop_car:
 print(item)
 print('END '.center(40,'-'))
 print('Your balance is [%s]'%salary)
 exit_flag =True
 elif user_choice == 'c' or user_choice == 'check':
 print('purchased products are:'.center(40, '-'))
 for item in shop_car:
 print(item)
 print('Your balance is %d' % salary)
 print('Check '.center(40, '-'))
 else:
 print('Incorrect input ,please input again!!')

2、程序运行结果

input your salary:10000
-----------welcome to our shoping mall------------
------------------product list :------------------
0 Iphone 5888
1 Mac Air 8000
2 XiaoMi 19.9
3 coffee 30
4 Tesla 820000
5 Bike 700
6 Cloth 200
[q=quit,c=check] what do you want to buy?:0
added [[('Iphone', 5888)]] into shop car ,yourcurrent balence is 4112
------------------product list :------------------
0 Iphone 5888
1 Mac Air 8000
2 XiaoMi 19.9
3 coffee 30
4 Tesla 820000
5 Bike 700
6 Cloth 200
[q=quit,c=check] what do you want to buy?:1
Your balance is [4112],cannot buy the product!
------------------product list :------------------
0 Iphone 5888
1 Mac Air 8000
2 XiaoMi 19.9
3 coffee 30
4 Tesla 820000
5 Bike 700
6 Cloth 200
[q=quit,c=check] what do you want to buy?:c
shop car list are [[('Iphone', 5888)]],your balance is 4112
------------------product list :------------------
0 Iphone 5888
1 Mac Air 8000
2 XiaoMi 19.9
3 coffee 30
4 Tesla 820000
5 Bike 700
6 Cloth 200
[q=quit,c=check] what do you want to buy?:4
Your balance is [4112],cannot buy the product!
------------------product list :------------------
0 Iphone 5888
1 Mac Air 8000
2 XiaoMi 19.9
3 coffee 30
4 Tesla 820000
5 Bike 700
6 Cloth 200
[q=quit,c=check] what do you want to buy?:q
--------purchased products are:---------
('Iphone', 5888)
------------------END ------------------
Your balance is [4112]
Process finished with exit code 0

3、学习到的知识点

（1）print('product list :'.center(50,'-'))

>>> print('product list :'.center(50,'-'))
------------------product list :------------------

（2）for item in enumerate(product_list):

>>> for item in enumerate(product_list):
print(item)
(0, ('Iphone', 5888))
(1, ('Mac Air', 8000))
(2, ('XiaoMi', 19.9))
(3, ('coffee', 30))
(4, ('Tesla', 820000))
(5, ('Bike', 700))
(6, ('Cloth', 200))

enumerate函数返回一个生成器对象：（index,item）的元组。

（3）这里使用了列表+元组的形式存储商品列表，而不是字典，因为字典是无序的，每次打印顺序都不一样，而且不能通过索引进行取值。