python3.x Day2 购物车程序练习

购物车程序：

1、启动程序后，输入用户名密码后，如果是第一次登录，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

6、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

7、允许查询之前的消费记录

用户验证使用之前博文中的程序，进行一定改动。主要是传参和调用后续的购物车程序。此处不再描述。

购物车入口：

m_shop.py

#!/usr/bin/env python
# -*- coding:utf-8 -*-
# Author: Wang Yue

import mode_shop,sys,random,os

def show_me(shopcart,user_guest):
    # 打印购买结果：
    print("you choose:")
    # 加工输出买得东西列表：按照每种货物的，货物名称，购买数量，单价/小计 的方式输出
    with open("shopping_cart_db.doo", mode="a+", encoding="utf-8") as shop_cart_db:
        for it in shopcart.get_items():
            print(
                "item name:\033[1;35m {_it_name} \033[0m!,num:\033[1;35m {_num} \033[0m!,val:\033[1;35m {_val} \033[0m!/\033[1;35m {_vals} \033[0m!".format(
                    _it_name=it[0].get_item_name(), _num=it[1], _val=it[0].get_item_value(),
                    _vals=it[0].get_item_value() * it[1]))
            shop_cart_db.write("{shop_cart_id},{item_id},{_num}\n".format(shop_cart_id=shopcart.get_shopcart_id(),
                                                                          item_id=it[0].get_item_id(), _num=it[1]))
            # 输出购买总价格
            # 输出兜兜里还剩下的钱数
    with open("balance_db.doo", mode="a+", encoding="utf-8") as balance_db:
        print("your user_id is \033[1;35m {u_id} \033[0m!".format(u_id=user_guest.get_user_id()))
        print("all value is: \033[1;35m {_count} \033[0m!".format(_count=shopcart.get_count_val()))
        print("you surplus:\033[1;35m {_my} \033[0m!".format(_my=user_guest.get_user_val()))
        balance_db.write(
            "{u_id},{cart_id},{val}\n".format(u_id=user_guest.get_user_id(), cart_id=shopcart.get_shopcart_id(),
                                              val=user_guest.get_user_val()))

if __name__ == "__main__":
    items=[] #货物实例数组，存放的各种货物实例，与类中定义的items意义不同
    shopcart=mode_shop.shopping_cart() #初始化购物车实例
    #初始化货物实例
    with open("item_db.doo",mode="r",encoding="utf-8") as item_db: #从文件数据源中读出每个货物，初始化货物实例并放入items列表
        item_db.flush()
        item_db.seek(0)
        for it_info in item_db.readlines():
            it_info=it_info.strip()
            it_if=it_info.split(",")
            items.append(mode_shop.item(int(it_if[0]),it_if[1],int(it_if[2])))
    user_guest=mode_shop.user_guest() #初始化一个用户
    in_user_id=sys.argv[1]

    if in_user_id:
        #从装入之前的用户和购物车：
        if os.path.exists("balance_db.doo"): #装载用户之前的购物车情况，建立用户和购物车的关联
            with open("balance_db.doo",mode="r",encoding="utf-8") as load_user_db:
                lu=load_user_db.readlines()
                for load_user in lu :
                    load_user=load_user.strip()
                    l_user=load_user.split(",")
                    if in_user_id==l_user[0]:    #仅仅读取一个用户
                        user_guest.set_user_id(l_user[0])
                        user_guest.set_shopcart_id(l_user[1])
                        user_guest.set_user_val(int(l_user[2]))
                        break
            with open("balance_db.doo",mode="w",encoding="utf-8") as w_user_db: #装在后，需要将文件中，用户的涉及到的行删掉
                for line in lu:
                    if str(user_guest.get_user_id()) in line:
                        continue
                    w_user_db.write(line)

        if user_guest.get_user_id() != 0: #如果从用户余额文件中存在用户，则开始关联购物车，关联后，就删除文件中的信息
            if os.path.exists("shopping_cart_db.doo"):
                with open("shopping_cart_db.doo",mode="r",encoding="utf-8") as cart_db:
                    c_lines=cart_db.readlines()
                    for cl in c_lines:
                        c_info=cl.split(",")
                        if user_guest.get_shopcart_id() == c_info[0]: #读取全部购物车信息
                            shopcart.set_shopcart_id(c_info[0])
                            for item in items:
                                if int(c_info[1]) == item.get_item_id():
                                    shopcart.set_oneappend_item(item,int(c_info[2]))
                with open("shopping_cart_db.doo",mode="w",encoding="utf-8") as w_cart_db:
                    for line in c_lines:
                        if shopcart.get_shopcart_id() in line:
                            continue
                        w_cart_db.write(line)
    else:
        pass

    if  user_guest.get_shopcart_id() == 0:
        #生成随机id，用于描述关联，
        shopcart.set_shopcart_id("cart_{cart_id}".format(cart_id=random.randint(1000,9999)))
        user_guest.set_user_id(sys.argv[1])
        #描述用户和购物车的关联，就是让用户推个购物车去采购。
        user_guest.set_shopcart_id(shopcart.get_shopcart_id())

        #开始业务，输入逛超市带的钱数
        have_val = int(input("your val:"))
        user_guest.set_user_val(have_val)

    int_error = False  # 初始化一个标记，是否进行业务
    while not int_error:

        for it in items:
            #输出每个货物的信息，展示给用户
            print("id:{_id},{_name},val: {_val}".format(_id=it.get_item_id(),_name=it.get_item_name(),_val=it.get_item_value()))

        it_id=input("which one is you choice(id) or view or quit:")#接收想要购买的货物id，不是数字就退出，不是id就重新输入，是id进行业务

        if it_id.isdigit():
            it_id=int(it_id) #尝试转为整形
        elif it_id == "view":
            show_me(shopcart, user_guest)
        else:
            int_error=True

        if int_error: #如果输入的无法被转为数字，则认定是想结束程序，以下是结束过程
            show_me(shopcart,user_guest)
            sys.exit(0)

        for it in items: #在货物堆中找出想要买得货物
            if it.get_item_id()== it_id:
                it_num = input("how many {it_name} would you buy(int):".format(it_name=it.get_item_name()))
                if it_num.isdigit():
                    it_num = int(it_num)
                else:
                    print("you need input a number(int)")
                    break
                if user_guest.get_user_val() < it.get_item_value()*it_num: #判定兜兜里的钱是否够买
                    print("your money is not enough!!!!")
                    break

                user_guest.set_user_val(user_guest.get_user_val()-it.get_item_value()*it_num) #钱够的话就买
                shopcart.set_oneappend_item(it,it_num) #加入到购物车

定义类的文件mode_shop.py，货物类、购物车类、用户类：

#!/usr/bin/env python
# -*- coding:utf-8 -*-
# Author: Wang Yue

class shopping_cart(object):
    def __init__(self):
        self.items=[] #定义的二维数组，存放内容的单元素为[item,num]
        self.count_value=0
        self.id=0
    def set_oneappend_item(self,item,num): #加入一个货物，如果加过，就仅累加该货物的数量，否则加入新的元素。
        for its in self.items:
            if its[0].get_item_id() == item.get_item_id():
                its[1]=num+its[1]
                break
        else:
            self.items.append([item,num])

    def get_items(self): #获取购物车上的货物，及数量，就是那个二维数组
        return self.items
    def get_count_val(self):#获取购物车上当前的总价格，二维数组中的定义是货物和数量，所以算法如下。太粗暴了
        for item in self.items:
            self.count_value=self.count_value+item[0].get_item_value()*item[1]
        return self.count_value
    def set_shopcart_id(self,sc_id):
        self.id=sc_id
    def get_shopcart_id(self):
        return self.id

class item(object): #货物类
    def __init__(self,it_id,it_name,it_value):
        self.item_id=it_id #货物id
        self.item_name=it_name #货物名称
        self.item_value=it_value #货物单价

    def set_item_name(self,it_name):
        self.item_name=it_name
    def get_item_name(self):
        return self.item_name

    def set_item_value(self,it_val):
        self.item_value=it_val
    def get_item_value(self):
        return self.item_value

    def set_item_id(self,it_id):
        self.item_id=it_id
    def get_item_id(self):
        return self.item_id

class user_guest(object):
    def __init__(self):
        self.user_id=0
        self.shopcart_id=0
        self.val=0
    def set_user_id(self,u_id):
        self.user_id=u_id
    def get_user_id(self):
        return self.user_id
    def set_shopcart_id(self,sc_id):
        self.shopcart_id=sc_id
    def get_shopcart_id(self):
        return self.shopcart_id
    def set_user_val(self,val):
        self.val=val
    def get_user_val(self):
        return self.val

附：用的文件作为数据源：

存放购物车货物存放信息shopping_cart_db.doo：

cart_4871,3,6
cart_4871,4,6
cart_4871,3,6
cart_4871,4,6

存放货物信息item_db.doo：

1,iphone,10000
2,bag,300
3,book,50
4,note,5
5,smoke,8
6,box,10
7,fire,1
8,table,3000
9,pc,7000

存放已经存放货物关联信息balance_db.doo:

user_2592,cart_4871,49550
user_2592,cart_4871,49550

维护商品的脚本：supply_item.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# author : Wang Yue

import sys

while True:
    print('''cmd:
    view : all items
    insert : id(int),name(str),price(int) insert one into DB
    update: id(int),name(str),price(int) update one from DB
    delete: id(int) delete one from DB
    quit: quit me
    ''')
    cmd=input("cmd>> ")
    command=cmd.split()
    if command[0] == "view":
        with open("item_db.doo",mode="r",encoding="utf-8") as view_db:
            lines=view_db.readlines()
            for line in lines:
                line=line.strip()
                print(line)
    elif  command[0] == "insert":
        with open("item_db.doo",mode="a+",encoding="utf-8") as apd_db:
            item=input("item info:")
            it_info=item.split(",")
            if len(it_info) == 3:
                apd_db.write("{id},{name},{prc}\n".format(id=it_info[0],name=it_info[1],prc=it_info[2]))
            else:
                continue
    elif command[0] == "update":
        with open("item_db.doo",mode="r",encoding="utf-8") as r_it_db:
            lines=r_it_db.readlines()
        info=input("item info>> (id,name,prc):")
        info=info +"\n"
        info_id=info.split(",")
        is_break=0
        for line in lines:
            line_old = line.split(",")
            if info_id[0] != line_old[0]:
                is_break=1
            else:
                is_break=0
                break
        if is_break==1:
            print("not found it from DB")
            continue
        with open("item_db.doo",mode="w",encoding="utf-8") as w_it_db:
            for line_n in lines:
                if info_id[0] == line_n[0]:
                    line_n=info
                w_it_db.write(line_n)

    elif command[0] == "delete":
        with open("item_db.doo",mode="r",encoding="utf-8") as dr_it_db:
            lines=dr_it_db.readlines()
            d_info=input("input item's id:")
        with open("item_db.doo",mode="w",encoding="utf-8") as dw_it_db:
            for line_n in lines:
                line_n_l=line_n.split(",")
                if line_n_l[0]==d_info:
                    continue
                dw_it_db.write(line_n)
    elif command[0] =="quit":
        sys.exit(0)
        break
    else:
        continue