python购物车程序

数据结构：
goods = [
{"name": "电脑", "price": 1999},
{"name": "鼠标", "price": 10},
{"name": "游艇", "price": 20},
{"name": "美女", "price": 998},
......
]

基本需求：
1. 启动程序后，输入用户名密码后，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，商品已加入购物车等消息，需高亮显示

升级需求：
1. 用户下一次登录后，输入用户名密码，直接回到上次的状态，即上次消费的余额什么的还是那些，再次登录可继续购买
2. 允许查询之前的消费记录

代码一

#!/usr/bin/env python
# coding: utf-8

import json, sys, os

def user_login():
    name_list = ["zhangsan","lisi","wangwu"]  # 用户名列表
    passwd_list = ["zhangsan666","lisi666","wangwu666"]  # 用户的密码列表
    count = [0, 0, 0]  # 用户登录密码错误的次数计数
    while True:
        name_index = 999999  # 定义一个不存在的用户的下标
        name = input("请输入你的姓名：").strip()
        passwd = input("请输入你的密码：").strip()
        with open("lockedname.txt","r+", encoding="utf-8") as f:
            locked_name = "".join(f.readlines()).splitlines()
            if name in locked_name:
                print("用户已经被锁定，请联系管理员")
                continue
        for i in range(len(name_list)):
            if name == name_list[i]:
                name_index = name_list.index(name_list[i])
        if name_index == 999999:
            print("用户名不存在，请重新输入")
            continue
        if name == name_list[name_index] and passwd == passwd_list[name_index]:  # 判断用户名密码
            print("欢迎 %s 同学"%(name_list[name_index]))
            return(0, name)

        else:
            count[name_index] += 1  # 同一个用户名输错密码加一
            print("密码错误")
            if count[name_index] == 3 :
                print("3次密码错误，用户账号已被锁定")
                with open("lockedname.txt","a+", encoding="utf-8") as f:
                    f.writelines(name_list[name_index]+"
")
                break

result = user_login() # 调用用户登录函数
if result[0] != 0: # 验证是否登录成功
    sys.exit()
goods = [
    {"name": "电脑", "price": 1999},
    {"name": "鼠标", "price": 10},
    {"name": "游艇", "price": 20},
    {"name": "美女", "price": 998}
]

with open("expenses_record.txt", "r", encoding="utf-8") as f:
    if os.path.getsize("expenses_record.txt") == 0: # 判断是否有登录过
        expenses_record = {}
        record = []
        goods_list = []
        salary = int(input("请输入您的工资：").strip())
    else:
        expenses_record = json.load(f)
        try:
            record = expenses_record[result[1]]
            goods_list = record[1]
            bought_list = " ".join(goods_list)
            print("账户余额：",record[0], "已购买物品：", bought_list) # 打印记录的余额，和记录的已买物品
            salary = record[0]
        except KeyError:
            record = []
            goods_list = []
            salary = int(input("请输入您的工资：").strip())
while True:
    for i, good in enumerate(goods): # 生成对应序号
        print(i, good["name"], good["price"])
    choice = input("请输入您要购买的商品编号或q退出：").strip()
    if choice.lower() == "q":
        your_good = ""
        for good in goods_list:
            your_good += good +" "
        print("您已购买的商品为：", your_good)
        print("您的余额为%s元："% (salary))
        record = [salary, goods_list]
        user = result[1]
        expenses_record[user] = record
        with open("expenses_record.txt", "w", encoding="utf-8") as f:
            f.write(json.dumps(expenses_record))
        break
    choice = int(choice)
    if salary < goods[choice]["price"]:
        need_money = goods[choice]["price"] - salary
        print("您的余额不足，还差%s元"% ( need_money ))
    else:
        salary = salary - goods[choice]["price"]
        goods_list.append(goods[choice]["name"])
        print("33[31;1m您已购买:%s33[0m"%(goods[choice]["name"]), "33[31;1m您的余额为:%s元33[0m"%(salary))

代码二（修改版）

#!/usr/bin/env python
# coding: utf-8

import json, sys, os

def user_login():
    user = {
        "zhangsan": ["zhangsan666", 3, False],
        "lisi": ["lisi666", 0, True],
        "wangwu": ["wangwu666", 0, True]
    }  # 用户名：[密码，密码输错次数，False锁定用户]
    while True:
        name = input("请输入你的姓名：").strip()
        try:
            with open("lockedname.txt", "r+", encoding="utf-8") as f:
                user = json.load(f)  # 若是有lockedname.txt文件，则user重新赋值
        except Exception as err:
            pass
        if name not in user:
            print("用户名不存在，请重新输入")
            continue
        elif user[name][2] == False:
            print("用户已经被锁定，请联系管理员")
            continue
        elif name in user:
            passwd = input("请输入你的密码：").strip()
            if passwd == user[name][0]:  # 判断用户名密码
                print("欢迎 %s 同学" % (name))
                user[name][1] = 0
                with open("lockedname.txt", "w", encoding="utf-8") as f:
                    json.dump(user, f)
                break
            else:
                user[name][1] += 1  # 同一个用户名输错密码加一
                print("密码错误")
                if user[name][1] >= 3:
                    print("用户账号已被锁定")
                    user[name][2] = False
                with open("lockedname.txt", "w", encoding="utf-8") as f:
                    json.dump(user, f)


result = user_login() # 调用用户登录函数
if result[0] != 0: # 验证是否登录成功
    sys.exit()
goods = [
    {"name": "电脑", "price": 1999},
    {"name": "鼠标", "price": 10},
    {"name": "游艇", "price": 20},
    {"name": "美女", "price": 998}
]

with open("expenses_record.txt", "r", encoding="utf-8") as f:
    if os.path.getsize("expenses_record.txt") == 0: # 判断是否有登录过
        expenses_record = {}
        record = []
        goods_list = []
        salary = int(input("请输入您的工资：").strip())
    else:
        expenses_record = json.load(f)
        try:
            record = expenses_record[result[1]]
            goods_list = record[1]
            bought_list = " ".join(goods_list)
            print("账户余额：",record[0], "已购买物品：", bought_list) # 打印记录的余额，和记录的已买物品
            salary = record[0]
        except KeyError:
            record = []
            goods_list = []
            salary = int(input("请输入您的工资：").strip())
while True:
    for i, good in enumerate(goods): # 生成对应序号
        print(i, good["name"], good["price"])
    choice = input("请输入您要购买的商品编号或q退出：").strip()
    if choice.lower() == "q":
        your_good = ""
        for good in goods_list:
            your_good += good +" "
        print("您已购买的商品为：", your_good)
        print("您的余额为%s元："% (salary))
        record = [salary, goods_list]
        user = result[1]
        expenses_record[user] = record
        with open("expenses_record.txt", "w", encoding="utf-8") as f:
            f.write(json.dumps(expenses_record))
        break
    choice = int(choice)
    if salary < goods[choice]["price"]:
        need_money = goods[choice]["price"] - salary
        print("您的余额不足，还差%s元"% ( need_money ))
    else:
        salary = salary - goods[choice]["price"]
        goods_list.append(goods[choice]["name"])
        print("33[31;1m您已购买:%s33[0m"%(goods[choice]["name"]), "33[31;1m您的余额为:%s元33[0m"%(salary))

 代码三（修改版）

#!/usr/bin/env python
# coding=utf-8
# __author__ = "zhaohongwei"
# Date: 2019/3/9

import json, sys, os

def user_login():
    user = {
        "zhangsan": ["zhangsan666", 3, False],
        "lisi": ["lisi666", 0, True],
        "wangwu": ["wangwu666", 0, True]
    }  # 用户名：[密码，密码输错次数，False锁定用户]
    while True:
        name = input("请输入你的姓名：").strip()
        try:
            with open("lockedname.txt", "r+", encoding="utf-8") as f:
                user = json.load(f)  # 若是有lockedname.txt文件，则user重新赋值
        except Exception as err:
            pass
        if name not in user:
            print("用户名不存在，请重新输入")
            continue
        elif user[name][2] == False:
            print("用户已经被锁定，请联系管理员")
            continue
        elif name in user:
            passwd = input("请输入你的密码：").strip()
            if passwd == user[name][0]:  # 判断用户名密码
                print("欢迎 %s 同学" % (name))
                user[name][1] = 0
                with open("lockedname.txt", "w", encoding="utf-8") as f:
                    json.dump(user, f)
                return (0, name)

            else:
                user[name][1] += 1  # 同一个用户名输错密码加一
                print("密码错误")
                if user[name][1] >= 3:
                    print("用户账号已被锁定")
                    user[name][2] = False
                with open("lockedname.txt", "w", encoding="utf-8") as f:
                    json.dump(user, f)


result = user_login() # 调用用户登录函数
print(result)
if result[0] != 0: # 验证是否登录成功
    sys.exit()

goods = [
    {"name": "电脑", "price": 1999},
    {"name": "鼠标", "price": 10},
    {"name": "游艇", "price": 20},
    {"name": "美女", "price": 998}
]

with open("expenses_record.txt", "r", encoding="utf-8") as f:
    if os.path.getsize("expenses_record.txt") == 0: # 判断是否有登录过
        expenses_record = {}
        expenses_record[result[1]] = {
                           "credit": 0,
                           "cart_history": {},  # 购物车历史记录 商品名/单价/数量
                           "credit_balance": 0,  # 余额
                           "cash": 0,
                           "frozen": False
                  }
        record = expenses_record[result[1]]
        goods_list = expenses_record[result[1]]["cart_history"]
        salary = int(input("请输入您的工资：").strip())
    else:
        expenses_record = json.load(f)
        try:
            record = expenses_record[result[1]]
            goods_list = record["cart_history"]
            bought_list = " ".join(goods_list)
            print("账户余额：",record["credit_balance"], "已购买物品：", bought_list) # 打印记录的余额，和记录的已买物品
            salary = record["credit_balance"]
        except KeyError as err:
            print(err)
            record = expenses_record[result[1]] = {}
            goods_list = expenses_record[result[1]]["cart_history"] = {}
            salary = int(input("请输入您的工资：").strip())
while True:
    for i, good in enumerate(goods): # 生成对应序号
        print(i, good["name"], good["price"])
    choice = input("请输入您要购买的商品编号或q退出：").strip()
    if choice.lower() == "q":
        your_good = ""
        for good in goods_list:
            your_good += good +" "+str(goods_list[good][1])+"个"+" "
        print("您已购买的商品为：%s"%(your_good))
        print("您的余额为%s元："% (salary))
        record["credit"] = 0
        record["cart_history"] = goods_list
        record["credit_balance"] = salary  # 余额
        record["cash"] = 0
        record["frozen"] = False
        user = result[1]
        expenses_record[user] = record
        with open("expenses_record.txt", "w", encoding="utf-8") as f:
            f.write(json.dumps(expenses_record))
        break
    choice = int(choice)
    if salary < goods[choice]["price"]:
        need_money = goods[choice]["price"] - salary
        print("您的余额不足，还差%s元"% ( need_money ))
    else:
        salary = salary - goods[choice]["price"]
        num = 1
        if goods[choice]["name"] in goods_list:
            num = goods_list[goods[choice]["name"]][1]
            num += 1
        goods_list[goods[choice]["name"]] = [goods[choice]["price"], num]
        print("33[31;1m您已购买:%s33[0m"%(goods[choice]["name"]), "33[31;1m您的余额为:%s元33[0m"%(salary))