Python s12 Day2 笔记及作业

1. 元组的元素不可修改，但元组的元素的元素可以被修改。

2. name="eric"

print(name.center(20, "*")

3. list=['a', 'b', 'c', 'd']

str = '-'.join(list)

4. sys.argv 处理参数

maketrans()
语法
maketrans()方法语法：
str.maketrans(intab, outtab)
参数
intab -- 字符串中要替代的字符组成的字符串。
outtab -- 相应的映射字符的字符串。
返回值
返回字符串转换后生成的新字符串。
实例
以下实例展示了使用maketrans() 方法将所有元音字母转换为指定的数字：
#!/usr/bin/python
# -*- coding: UTF-8 -*-

from string import maketrans   # 必须调用 maketrans 函数。

intab = "aeiou"
outtab = ""
trantab = maketrans(intab, outtab)

str = "this is string example....wow!!!";
print(str.translate(trantab));
以上实例输出结果如下：
th3s 3s str3ng 2x1mpl2....w4w!!!

作业一：

• 购物商城
• 商品展示，价格
• 买，加入购物车
• 付款，钱不够

python3代码：

一共三个模块： 1. login模块负责登录  2.shopmall模块负责购物功能函数实现 3.shopcart模块为主程序

1. login

 import time

 def login():
     input_name = input("Please input your user name : ").strip()
     user_lockfile = open("user_lockfile.txt", "r+")
     user_file = open("user_file.txt")
     user_list = user_file.readlines()
     for i in range(3):
         input_passwd = input("Please input your password : ").strip()
         #查找被锁用户列表判断是否被锁住
         if input_name in [locked_user.rstrip() for locked_user in user_lockfile.readlines()]:
             print("Sorry, your account is locked!")
             user_file.close()
             user_lockfile.close()
             exit(1)
         else: #没有被锁住，查找用户列表
             if input_name not in [user_record.split()[0] for user_record in user_list]:
                 print("Sorry, your account doesn't exist!")
                 user_file.close()
                 user_lockfile.close()
                 exit(2)
             else: #用户存在，判断密码是否正确，正确跳出循环
                 input_record = input_name + ' ' + input_passwd
                 money = 0
                 for user_record in user_list:
                     user_info = user_record.split()[0]+' '+user_record.split()[1]
                     if input_record == user_info:
                         #money = int(user_record.split()[2])
                         print("Logging in...")
                         time.sleep(1)
                         user_file.close()
                         user_lockfile.close()
                         return input_name
                 else:#密码不正确，判断错误次数，错误三次（i=2）将用户锁住
                     if i == 2:
                         user_lockfile.write(input_name + "\n")
                         print("Sorry, you're locked!")
                         user_file.close()
                         user_lockfile.close()
                         exit(3)
                     else:#剩余机会数 2-i
                         chance = 2 - i
                         print("Wrong password! %s chances left!" % chance)

 def get_money(username):
     user_file = open("user_file.txt")
     for line in user_file.readlines():
         if username == line.split()[0]:
             money = line.split()[2]
     user_file.close()
     return money

 def update_money(username, old, new):
     with open("user_file.txt", 'r') as file:
         lines = file.readlines()
     with open("user_file.txt", 'w') as file:
         for line in lines:
             if line.split()[0] == username:
                 line = line.replace(str(old), str(new))
             file.write(line)

2. shopmall

 import time
 import homework3.login as login_module

 FIRST_LAYER_CHOICE = ''
 CART = {}
 USERNAME = ''
 CART_CHANGE_FLAG = ''

 def input_verify(choice):
     if str.isdigit(choice):
         choice = int(choice)
     return choice

 #欢迎界面框架
 def framework_show(username='', cart={}):
     global USERNAME
     USERNAME = username
     money = input_verify(login_module.get_money(username))
     print('''
 #############################################################
 *                                                           *
 *             Welcome to Wayne's Shopping Mall              *
 *                                                           *
 #############################################################
     ''', end='')
     userstring = "用户:%s\t余额:%d\t购物车:%d" % (username, money, len(cart))
     print(userstring.center(50))

 #商品总展示框架，一级菜单
 def goods_show(goods_dict):
     global FIRST_LAYER_CHOICE
     print("=============================================================")
     print("编号\t名称\t\t\t价格\t\t库存")
     print("=============================================================")
     for key in goods_dict.keys():
         name,price,inventory = goods_dict[key].values()
         print("%-4s\t%-12s\t%-4d\t\t%-4d" % (key, name, price, inventory))
     print("=============================================================")
     goods_input = input("请选择:\t编号(1-%d)|购物车(c)|结账(p)|退出(q) : " % max(key for key in goods_dict.keys()))
     goods_input = input_verify(goods_input)
     if goods_input == 'q':
         exit(0)
     elif goods_input == 'c' or goods_input == 'p' or goods_input in goods_dict.keys():
         FIRST_LAYER_CHOICE = goods_input
     else:
         print("输入错误！")
         FIRST_LAYER_CHOICE = ''
         time.sleep(2)

     while FIRST_LAYER_CHOICE:
         if FIRST_LAYER_CHOICE in goods_dict.keys():  #若选择商品编号，则调用商品信息展示函数
             goods_info(FIRST_LAYER_CHOICE, goods_dict)
         elif FIRST_LAYER_CHOICE == 'c':
             cart_show(goods_dict)
         elif FIRST_LAYER_CHOICE == 'p':
             pay_show()

 #选中商品进入二级菜单商品信息展示
 def goods_info(choice, goods_dict):
     global FIRST_LAYER_CHOICE
     name,price,inventory = goods_dict[choice].values()
     print("【编号: %s\t名称: %s\t价格: %d(元)\t库存: %d】" % (choice, name, price, inventory))
     if inventory == 0:
         print("无库存！")
         FIRST_LAYER_CHOICE = ''
         time.sleep(2)
     else:
         goods_num_input = input("请输入购买数量(库存%d)|返回(b)|退出(q): " % inventory)
         goods_num_input = input_verify(goods_num_input)
         if goods_num_input == 'q':
             exit(0)
         elif goods_num_input == 'b':  #若返回，则将全局变量赋值
             FIRST_LAYER_CHOICE = ''
         elif type(goods_num_input) is int and goods_num_input > 0 and goods_num_input <= inventory: #若输入数量在库存内
             add_cart(goods_dict, goods_num_input) #调用添加购物车函数
         else:
             print("输入错误！")
             time.sleep(1)

 #商品添加购物车功能实现
 def add_cart(goods_dict, goods_num):
     global FIRST_LAYER_CHOICE
     global CART
     global USERNAME

     name, price, inventory = goods_dict[FIRST_LAYER_CHOICE].values()
     confirm = input("确认购买%d个<%s>? y/n: " % (goods_num, name))
     if confirm == 'n':
         FIRST_LAYER_CHOICE = ''
     elif confirm == 'y':
         inventory = inventory - goods_num
         goods_dict[FIRST_LAYER_CHOICE]['inventory'] = inventory  #更新库存, 添加购物车不扣余额
         if FIRST_LAYER_CHOICE in CART.keys(): #若购物车中存在该商品，直接修改数量，否则添加至购物车
             CART[FIRST_LAYER_CHOICE]['num'] += goods_num
         else:
             CART[FIRST_LAYER_CHOICE] = {'name':name, 'price':price,'num':goods_num}
         print("添加购物车成功！")
         FIRST_LAYER_CHOICE = ''
     else:
         print("输入错误！")
     #return cart_dict

 def cart_show(goods_dict):
     global CART
     global FIRST_LAYER_CHOICE
     global CART_CHANGE_FLAG
     print('''
 -------------------------------------------------------------
 *                      Shopcart                             *
 -------------------------------------------------------------
 编号\t物品\t\t\t单价\t\t数量''')
     for i in sorted([i for i in CART.keys()]):
         name = CART[i]['name']
         price = CART[i]['price']
         num = CART[i]['num']
         print("%-8d%-12s\t%-4d\t\t%-4d" % (i, name, price, num))
     print("-------------------------------------------------------------")
     CART_CHANGE_FLAG = input("请选择  修改(c)|结账(p)|返回(b)|退出(q) : ")
     if CART_CHANGE_FLAG == 'q': exit(0)
     elif CART_CHANGE_FLAG == 'b':
         FIRST_LAYER_CHOICE = ''
     elif CART_CHANGE_FLAG == 'p':
         pay_show()
     elif CART_CHANGE_FLAG == 'c':
         while CART_CHANGE_FLAG: #循环修改商品，直到用户在修改商品界面选b返回
             cart_modify(goods_dict)
     else:
         print("输入错误！")

 def cart_modify(goods_dict):
     global CART
     global FIRST_LAYER_CHOICE
     global CART_CHANGE_FLAG
     if CART == {}:    #若购物车为空，返回选购商品
         print("购物车为空！请选购商品！")
         time.sleep(1)
         FIRST_LAYER_CHOICE = ''
         CART_CHANGE_FLAG = ''
     else:
         print('''
 -------------------------------------------------------------
 *                      Shopcart                             *
 -------------------------------------------------------------
 编号\t物品\t\t\t单价\t\t数量''')
         for i in sorted([i for i in CART.keys()]):
             name = CART[i]['name']
             price = CART[i]['price']
             num = CART[i]['num']
             print("%-8d%-12s\t%-4d\t\t%-4d" % (i, name, price, num))
         print("-------------------------------------------------------------")
         change_choice = input("请输入要修改的商品编号, 返回<b>: ")
         change_choice = input_verify(change_choice)
         if change_choice == 'b':
             CART_CHANGE_FLAG = ''
         else:
             if change_choice not in CART.keys():
                 print("输入错误！")
             else:
                 name, price, num = CART[change_choice].values()
                 print("【编号: %s\t名称: %s\t价格: %d(元)\t数量: %d】" % (change_choice, name, price, num))
                 inventory_total = goods_dict[change_choice]['inventory'] + num   #由于没付款，这里显示 总库存=当前库存+购物车数量
                 change_num = input("请输入要购买的数量, 库存%d: " % inventory_total)
                 change_num = input_verify(change_num)
                 if change_num in range(1,inventory_total+1):
                     confirm = input("确认购买%d个<%s>? y/n: " % (change_num, name))
                     if confirm == 'y':
                         CART[change_choice]['num'] = change_num
                         inventory = inventory_total - change_num  #修改当前库存为 总库存-修改后的购物车数量
                         goods_dict[change_choice]['inventory'] = inventory
                     elif confirm == 'n':
                         pass
                     else:
                         print("输入错误！")
                 elif change_num == 0:
                     confirm = input("确认从购物车清除<%s>? y/n: " % name)
                     if confirm == 'y':
                         CART.pop(change_choice) #从购物车清除后，显示当前库存为总库存
                         goods_dict[change_choice]['inventory'] = inventory_total
                         if CART == {}:
                             CART_CHANGE_FLAG = ''
                     elif confirm == 'n':
                         pass
                     else:
                         print("输入错误！")
                 else:
                     print("输入错误！")

 def pay_show():
     global USERNAME
     global CART
     global FIRST_LAYER_CHOICE
     if CART == {}:
         print("购物车为空！请选购商品！")
         time.sleep(1)
         FIRST_LAYER_CHOICE = ''
     else:
         total_price = 0
         print("*************************************************************")
         print("%-8s%-12s%-8s%-8s" % ("编号", "商品", "数量", "总价"))
         for i in CART.keys():
             name = CART[i]['name']
             num = CART[i]['num']
             price = CART[i]['price']
             goods_price = num * price
             total_price += goods_price
             print("%-10d%-14s%-10d%-4d" % (i, name, num, goods_price))
         print("*************************************************************")
         money = input_verify(login_module.get_money(USERNAME))
         print("购物车总价 : %d\t|\t当前余额 : %d" % (total_price, money))
         if money < total_price:   #若用余额不足以支付购物车，提示并返回
             print("余额不足！请充值！")
             time.sleep(1)
             FIRST_LAYER_CHOICE = 'c' if FIRST_LAYER_CHOICE == 'c' else ''
         else:
             pay__input = input("确认购买上述物品？ y/n : ")
             if pay__input == 'y':
                 left = money - total_price
                 login_module.update_money(USERNAME, money, left)
                 print("付款成功！ 余额 %d 元。" % left)
                 time.sleep(1)
                 exit(0)
             elif pay__input == 'n':
                 FIRST_LAYER_CHOICE = 'c' if FIRST_LAYER_CHOICE == 'c' else ''
             else:
                 print("输入错误！")

 def purchase(username, goods_dict):
     while True:
         framework_show(username)
         goods_show(goods_dict)

3. shopcart

 import homework3.login as login_module
 import homework3.shopmall as shopmall

 GOODS = {1:{'name':'iphone8', 'price':6888, 'inventory':30},
          2:{'name':'iphoneX', 'price':8388, 'inventory':8},
          3:{'name':'ipad mini4', 'price':2888, 'inventory':20},
          4:{'name':'MI MIX2', 'price':3288, 'inventory':25},
          5:{'name':'MEIZU Pro8', 'price':2488, 'inventory':2}}

 if __name__ == "__main__":
     username = login_module.login()
     shopmall.purchase(username, GOODS)

4. 用户信息记录文件

 wayne 123 1999829036
 kevin 123 20000
 root shroot123 3000

5.  用户锁定记录文件

 kevin
 james