知识点：
1、prettytable模块使用、os.system("clear")模块使用
2、文件操作（增删改查）
3、函数使用（实参、形参）
4、python中对于显示终端颜色的处理
需求:
1、启动程序后，输入用户名密码后，如果是第一次登陆，让用户输入工资，然后打印商品列表
2、允许用户根据商品编号购买商品
3、用户选择商品后，检测余额是否够，够的话就直接扣款，不够就提醒
4、可随时退出，退出时打印已购买商品和余额
5、在用户使用过程中，关键输出，如余额，商品，商品已加入购物车等消息，需高亮显示
6、用户下一次登陆后，输入用户名密码，直接回到上次的状态，即消费的余额什么的还是那些，再次登录可继续购买
7、允许查询之前的消费记录
代码实现：
注意：程序启动前必须创建一个名为db.txt的文件，用于保存用户信息
#!/usr/bin/env python #-*- coding=utf-8 -*- #author:sunwei #date:2017-9-20 1:48 import time import os from prettytable import PrettyTable shopping_list = [] username_password = [] product_info = [ ("bike",700), ("book",80), ("Iphone",4000), ("water",10), ("noodles",8) ] #提示欢迎语 def welcome(): print("欢迎%s登陆购物系统..."%username) time.sleep(2) os.system("clear") #输入为空格时循环输入 def get_salary(): while True: salary = input("请输入您的工资：").strip() if len(salary) == 0: continue else: break return salary #def first_shopping_system(salary,username,password) def shopping_system(salary,password,username,product_info,xiaofei_history,file7): #打印商品列表,用户输入商品编号,并检测余额是否足够 while True: x = PrettyTable(["商品编号","商品名称","价格"]) x.align["商品编号"] = 1 x.padding_width = 1 print(" 33[31;40m") #print("以下为商品信息".center(50,"-")) for index,i in enumerate(product_info): x.add_row([index,i[0],i[1]]) print("商品列表如下".center(40,"-")) print(x," 33[0m") product_num = input("请输入需要购买的商品(输入商品编号即可,q退出)：").strip() if len(product_num) == 0: continue elif product_num == "q": count_info = open("db.txt.bak","a+",encoding="utf-8") for line in file7: if line.startswith(username): line1 = line.strip().split() line2 = line.replace(line1[2],str(salary)) count_info.write(line2) else: count_info.write(line) count_info.close() os.remove("db.txt") os.rename("db.txt.bak","db.txt") print("") print(" 33[31;40m您的余额为：%d 33[0m"%int(salary)) print(" 33[31;40m您本次消费情况如下： 33[0m") user_record = open(xiaofei_history,"a+",encoding="utf-8") for s1 in shopping_list: print(s1) user_record.write(s1[0]+" "+str(s1[1])+" ") user_record.close() exit() else: #判断用户输入是否为数字字符 if product_num.isdigit(): product_num = int(product_num) if product_num < len(product_info): p_price = product_info[product_num][1] salary = int(salary) if p_price <= salary: salary -= p_price shopping_list.append(product_info[product_num]) print("您的余额：%d"%salary) #是否还要继续购买 print(shopping_list) else: print("您的余额：%d"%salary) print("余额不足,请重新选择商品！") else: print("商品不存在！！！") else: print("输入有误,请重试") #判断用户名和密码是否为首次登陆 file1 = open("db.txt","r",encoding="utf-8") file7 = open("db.txt","r",encoding="utf-8") file8 = open("db.txt","a+",encoding="utf-8") #find_status = False password_times = 0 #username_times = 0 while True: username = input("请输入用户名：").strip() if len(username) == 0:continue for line in file1: if line: li = line line = line.strip().split() if username != line[0]: continue elif username == line[0]: while True: if password_times < 3: password = input("请输入密码：").strip() if len(password) == 0:continue if password != line[1]: password_times += 1 continue elif password == line[1]: print("输入成功！！！") welcome() salary = line[2] print(" 33[31;40m账户余额：%s 33[0m"%salary) print(" 33[1;34;40m以下为消费历史清单 33[0m".center(30,"-")) xiaofei_history = username + ".record" file2 = open(xiaofei_history,"r",encoding="utf-8") for i in file2: print(i.strip()) file2.close() shopping_system(salary,password,username,product_info,xiaofei_history,file7) exit() else: print("密码输入错误3次，请重新登陆！！！") exit() else: print("此用户为首次登陆！！！") while True: password = input("为账户设置密码（不能为空）：").strip() if len(password) == 0:continue salary = get_salary() while True: x = PrettyTable(["商品编号","商品名称","价格"]) x.align["商品编号"] = 1 x.padding_width = 1 print(" 33[31;40m") print("以下为商品信息".center(50,"-")) for index,i in enumerate(product_info): x.add_row([index,i[0],i[1]]) print(x," 33[0m") product_num = input("请输入需要购买的商品(输入商品编号即可,q退出)：").strip() if len(product_num) == 0: continue elif product_num == "q": file1.close() file7.close() file8.close() file9 = open("first_db.txt","w+",encoding="utf-8") file10 = open("db.txt","r",encoding="utf-8") #file9.write(username+" "+password+" "+str(salary)) for line in file10: if line: file9.write(line) else: continue file9.write(username+" "+password+" "+str(salary)+" ") file9.close() file10.close() os.remove("db.txt") os.rename("first_db.txt","db.txt") xiaofei_history = username + ".record" print("") print(" 33[31;40m您的余额为：%d 33[0m"%int(salary)) print(" 33[31;40m您本次消费情况如下： 33[0m") user_record = open(xiaofei_history,"a+",encoding="utf-8") for s1 in shopping_list: print(s1) user_record.write(s1[0]+" "+str(s1[1])+" ") user_record.close() exit() else: if product_num.isdigit(): product_num = int(product_num) if product_num < len(product_info): p_price = product_info[product_num][1] salary = int(salary) if p_price <= salary: salary -= p_price shopping_list.append(product_info[product_num]) print("您的余额：%d"%salary) #是否还要继续购买 print(shopping_list) else: print("您的余额：%d"%salary) print("余额不足,请重新选择商品！") else: print("商品不存在！！！") else: print("输入有误,请重试")
代码较为简陋以及繁琐，后期会进行改进...........