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

巴特西

Python s12 Day2 笔记及作业

作业一：

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