python3 购物车小程序，余额写入文件保存

python3 购物车小程序，余额写入文件保存

python3 购物车小程序，余额写入文件保存

#!/usr/bin/env python
# -*- coding:utf-8 -*-
# Author:Hiuhung Wangoods = (("MiNote3", 2499),("Bike", 799),("MacBook", 6999),("Coffee", 25),("RedMiNote3", 1099),("Python 3", 59)
)def main():'''入口:return:'''# 创建一个文件，用于存储余额。try:with open(&#', 'r') as f:data_str = f.read()if data_str and (not data_str.isspace()):  # 有内容，balance = int(data_str)else:    # 有文件，但没有内容balance = input("请输入您的钱包余额：")if balance.isnumeric():balance = int(balance)else:print("请输入正整数")exit()with open(&#', 'w') as f:f.write(str(balance))except FileNotFoundError as e:  # 没有这个文件，就创建并写入内容balance = input("请输入您的钱包余额：")if balance.isnumeric():balance = int(balance)else:print("请输入正整数")exit()with open(&#', 'w') as f:f.write(str(balance))finally:f.close()  # 关闭文件。go_back_flag = Trueshopping_list = []while go_back_flag:for i, j in enumerate(goods):print(i, j)user_chiose = input("钱包余额是：% .2f，您要买什么？" % (balance))if user_chiose == ("q" or "Q"):go_back_flag = Falsecontinueelif user_chiose.isnumeric():user_chiose = int(user_chiose)else:print("请输入上面的序号")continueif user_chiose <= len(goods) - 1:  #符合if goods[user_chiose][1] <= balance:   #买得起balance -= goods[user_chiose][1]with open(&#', 'w') as f:  # 更新余额（覆盖）f.write(str(balance))f.close()print("已将 %s 加入您的购物车" %(goods[user_chiose][0]))shopping_list.append(goods[user_chiose])else:print("余额不足，买不了。")else:print("超出范围，没有这个序号")print("您的钱包余额是：%.2f。" %(balance))if len(shopping_list) == 0:print("您都没有买东西")else:print("下面将列出你已购买的商品")for i in shopping_list:print(i)if __name__ == "__main__":main()

效果如下：

C: D:/Py/1704/day05/购物车.py
请输入您的钱包余额：6666
0 ('MiNote3', 2499)
1 ('Bike', 799)
2 ('MacBook', 6999)
3 ('Coffee', 25)
4 ('RedMiNote3', 1099)
5 ('Python 3', 59)
钱包余额是： 6666.00，您要买什么？3
已将 Coffee 加入您的购物车
0 ('MiNote3', 2499)
1 ('Bike', 799)
2 ('MacBook', 6999)
3 ('Coffee', 25)
4 ('RedMiNote3', 1099)
5 ('Python 3', 59)
钱包余额是： 6641.00，您要买什么？2
余额不足，买不了。
0 ('MiNote3', 2499)
1 ('Bike', 799)
2 ('MacBook', 6999)
3 ('Coffee', 25)
4 ('RedMiNote3', 1099)
5 ('Python 3', 59)
钱包余额是： 6641.00，您要买什么？1
已将 Bike 加入您的购物车
0 ('MiNote3', 2499)
1 ('Bike', 799)
2 ('MacBook', 6999)
3 ('Coffee', 25)
4 ('RedMiNote3', 1099)
5 ('Python 3', 59)
钱包余额是： 5842.00，您要买什么？q
您的钱包余额是：5842.00。
下面将列出你已购买的商品
('Coffee', 25)
('Bike', 799)Process finished with exit code 0

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