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 = "12345" 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
1 import time 2 3 4 def login(): 5 input_name = input("Please input your user name : ").strip() 6 user_lockfile = open("user_lockfile.txt", "r+") 7 user_file = open("user_file.txt") 8 user_list = user_file.readlines() 9 for i in range(3): 10 input_passwd = input("Please input your password : ").strip() 11 #查找被锁用户列表判断是否被锁住 12 if input_name in [locked_user.rstrip() for locked_user in user_lockfile.readlines()]: 13 print("Sorry, your account is locked!") 14 user_file.close() 15 user_lockfile.close() 16 exit(1) 17 else: #没有被锁住，查找用户列表 18 if input_name not in [user_record.split()[0] for user_record in user_list]: 19 print("Sorry, your account doesn't exist!") 20 user_file.close() 21 user_lockfile.close() 22 exit(2) 23 else: #用户存在，判断密码是否正确，正确跳出循环 24 input_record = input_name + ' ' + input_passwd 25 money = 0 26 for user_record in user_list: 27 user_info = user_record.split()[0]+' '+user_record.split()[1] 28 if input_record == user_info: 29 #money = int(user_record.split()[2]) 30 print("Logging in...") 31 time.sleep(1) 32 user_file.close() 33 user_lockfile.close() 34 return input_name 35 else:#密码不正确，判断错误次数，错误三次（i=2）将用户锁住 36 if i == 2: 37 user_lockfile.write(input_name + " ") 38 print("Sorry, you're locked!") 39 user_file.close() 40 user_lockfile.close() 41 exit(3) 42 else:#剩余机会数 2-i 43 chance = 2 - i 44 print("Wrong password! %s chances left!" % chance) 45 46 def get_money(username): 47 user_file = open("user_file.txt") 48 for line in user_file.readlines(): 49 if username == line.split()[0]: 50 money = line.split()[2] 51 user_file.close() 52 return money 53 54 def update_money(username, old, new): 55 with open("user_file.txt", 'r') as file: 56 lines = file.readlines() 57 with open("user_file.txt", 'w') as file: 58 for line in lines: 59 if line.split()[0] == username: 60 line = line.replace(str(old), str(new)) 61 file.write(line)
2. shopmall
1 import time 2 import homework3.login as login_module 3 4 5 FIRST_LAYER_CHOICE = '' 6 CART = {} 7 USERNAME = '' 8 CART_CHANGE_FLAG = '' 9 10 def input_verify(choice): 11 if str.isdigit(choice): 12 choice = int(choice) 13 return choice 14 15 16 #欢迎界面框架 17 def framework_show(username='', cart={}): 18 global USERNAME 19 USERNAME = username 20 money = input_verify(login_module.get_money(username)) 21 print(''' 22 ############################################################# 23 * * 24 * Welcome to Wayne's Shopping Mall * 25 * * 26 ############################################################# 27 ''', end='') 28 userstring = "用户:%s 余额:%d 购物车:%d" % (username, money, len(cart)) 29 print(userstring.center(50)) 30 31 32 #商品总展示框架，一级菜单 33 def goods_show(goods_dict): 34 global FIRST_LAYER_CHOICE 35 print("=============================================================") 36 print("编号 名称 价格 库存") 37 print("=============================================================") 38 for key in goods_dict.keys(): 39 name,price,inventory = goods_dict[key].values() 40 print("%-4s %-12s %-4d %-4d" % (key, name, price, inventory)) 41 print("=============================================================") 42 goods_input = input("请选择: 编号(1-%d)|购物车(c)|结账(p)|退出(q) : " % max(key for key in goods_dict.keys())) 43 goods_input = input_verify(goods_input) 44 if goods_input == 'q': 45 exit(0) 46 elif goods_input == 'c' or goods_input == 'p' or goods_input in goods_dict.keys(): 47 FIRST_LAYER_CHOICE = goods_input 48 else: 49 print("输入错误！") 50 FIRST_LAYER_CHOICE = '' 51 time.sleep(2) 52 53 while FIRST_LAYER_CHOICE: 54 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 55 goods_info(FIRST_LAYER_CHOICE, goods_dict) 56 elif FIRST_LAYER_CHOICE == 'c': 57 cart_show(goods_dict) 58 elif FIRST_LAYER_CHOICE == 'p': 59 pay_show() 60 61 62 63 64 #选中商品进入二级菜单商品信息展示 65 def goods_info(choice, goods_dict): 66 global FIRST_LAYER_CHOICE 67 name,price,inventory = goods_dict[choice].values() 68 print("【编号: %s 名称: %s 价格: %d(元) 库存: %d】" % (choice, name, price, inventory)) 69 if inventory == 0: 70 print("无库存！") 71 FIRST_LAYER_CHOICE = '' 72 time.sleep(2) 73 else: 74 goods_num_input = input("请输入购买数量(库存%d)|返回(b)|退出(q): " % inventory) 75 goods_num_input = input_verify(goods_num_input) 76 if goods_num_input == 'q': 77 exit(0) 78 elif goods_num_input == 'b': #若返回，则将全局变量赋值 79 FIRST_LAYER_CHOICE = '' 80 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 81 add_cart(goods_dict, goods_num_input) #调用添加购物车函数 82 else: 83 print("输入错误！") 84 time.sleep(1) 85 86 87 #商品添加购物车功能实现 88 def add_cart(goods_dict, goods_num): 89 global FIRST_LAYER_CHOICE 90 global CART 91 global USERNAME 92 93 name, price, inventory = goods_dict[FIRST_LAYER_CHOICE].values() 94 confirm = input("确认购买%d个<%s>? y/n: " % (goods_num, name)) 95 if confirm == 'n': 96 FIRST_LAYER_CHOICE = '' 97 elif confirm == 'y': 98 inventory = inventory - goods_num 99 goods_dict[FIRST_LAYER_CHOICE]['inventory'] = inventory #更新库存, 添加购物车不扣余额 100 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 101 CART[FIRST_LAYER_CHOICE]['num'] += goods_num 102 else: 103 CART[FIRST_LAYER_CHOICE] = {'name':name, 'price':price,'num':goods_num} 104 print("添加购物车成功！") 105 FIRST_LAYER_CHOICE = '' 106 else: 107 print("输入错误！") 108 #return cart_dict 109 110 def cart_show(goods_dict): 111 global CART 112 global FIRST_LAYER_CHOICE 113 global CART_CHANGE_FLAG 114 print(''' 115 ------------------------------------------------------------- 116 * Shopcart * 117 ------------------------------------------------------------- 118 编号 物品 单价 数量''') 119 for i in sorted([i for i in CART.keys()]): 120 name = CART[i]['name'] 121 price = CART[i]['price'] 122 num = CART[i]['num'] 123 print("%-8d%-12s %-4d %-4d" % (i, name, price, num)) 124 print("-------------------------------------------------------------") 125 CART_CHANGE_FLAG = input("请选择 修改(c)|结账(p)|返回(b)|退出(q) : ") 126 if CART_CHANGE_FLAG == 'q': exit(0) 127 elif CART_CHANGE_FLAG == 'b': 128 FIRST_LAYER_CHOICE = '' 129 elif CART_CHANGE_FLAG == 'p': 130 pay_show() 131 elif CART_CHANGE_FLAG == 'c': 132 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 133 cart_modify(goods_dict) 134 else: 135 print("输入错误！") 136 137 138 def cart_modify(goods_dict): 139 global CART 140 global FIRST_LAYER_CHOICE 141 global CART_CHANGE_FLAG 142 if CART == {}: #若购物车为空，返回选购商品 143 print("购物车为空！请选购商品！") 144 time.sleep(1) 145 FIRST_LAYER_CHOICE = '' 146 CART_CHANGE_FLAG = '' 147 else: 148 print(''' 149 ------------------------------------------------------------- 150 * Shopcart * 151 ------------------------------------------------------------- 152 编号 物品 单价 数量''') 153 for i in sorted([i for i in CART.keys()]): 154 name = CART[i]['name'] 155 price = CART[i]['price'] 156 num = CART[i]['num'] 157 print("%-8d%-12s %-4d %-4d" % (i, name, price, num)) 158 print("-------------------------------------------------------------") 159 change_choice = input("请输入要修改的商品编号, 返回<b>: ") 160 change_choice = input_verify(change_choice) 161 if change_choice == 'b': 162 CART_CHANGE_FLAG = '' 163 else: 164 if change_choice not in CART.keys(): 165 print("输入错误！") 166 else: 167 name, price, num = CART[change_choice].values() 168 print("【编号: %s 名称: %s 价格: %d(元) 数量: %d】" % (change_choice, name, price, num)) 169 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 170 change_num = input("请输入要购买的数量, 库存%d: " % inventory_total) 171 change_num = input_verify(change_num) 172 if change_num in range(1,inventory_total+1): 173 confirm = input("确认购买%d个<%s>? y/n: " % (change_num, name)) 174 if confirm == 'y': 175 CART[change_choice]['num'] = change_num 176 inventory = inventory_total - change_num #修改当前库存为 总库存-修改后的购物车数量 177 goods_dict[change_choice]['inventory'] = inventory 178 elif confirm == 'n': 179 pass 180 else: 181 print("输入错误！") 182 elif change_num == 0: 183 confirm = input("确认从购物车清除<%s>? y/n: " % name) 184 if confirm == 'y': 185 CART.pop(change_choice) #从购物车清除后，显示当前库存为总库存 186 goods_dict[change_choice]['inventory'] = inventory_total 187 if CART == {}: 188 CART_CHANGE_FLAG = '' 189 elif confirm == 'n': 190 pass 191 else: 192 print("输入错误！") 193 else: 194 print("输入错误！") 195 196 197 198 199 def pay_show(): 200 global USERNAME 201 global CART 202 global FIRST_LAYER_CHOICE 203 if CART == {}: 204 print("购物车为空！请选购商品！") 205 time.sleep(1) 206 FIRST_LAYER_CHOICE = '' 207 else: 208 total_price = 0 209 print("*************************************************************") 210 print("%-8s%-12s%-8s%-8s" % ("编号", "商品", "数量", "总价")) 211 for i in CART.keys(): 212 name = CART[i]['name'] 213 num = CART[i]['num'] 214 price = CART[i]['price'] 215 goods_price = num * price 216 total_price += goods_price 217 print("%-10d%-14s%-10d%-4d" % (i, name, num, goods_price)) 218 print("*************************************************************") 219 money = input_verify(login_module.get_money(USERNAME)) 220 print("购物车总价 : %d | 当前余额 : %d" % (total_price, money)) 221 if money < total_price: #若用余额不足以支付购物车，提示并返回 222 print("余额不足！请充值！") 223 time.sleep(1) 224 FIRST_LAYER_CHOICE = 'c' if FIRST_LAYER_CHOICE == 'c' else '' 225 else: 226 pay__input = input("确认购买上述物品？ y/n : ") 227 if pay__input == 'y': 228 left = money - total_price 229 login_module.update_money(USERNAME, money, left) 230 print("付款成功！ 余额 %d 元。" % left) 231 time.sleep(1) 232 exit(0) 233 elif pay__input == 'n': 234 FIRST_LAYER_CHOICE = 'c' if FIRST_LAYER_CHOICE == 'c' else '' 235 else: 236 print("输入错误！") 237 238 239 def purchase(username, goods_dict): 240 while True: 241 framework_show(username) 242 goods_show(goods_dict)
3. shopcart
1 import homework3.login as login_module 2 import homework3.shopmall as shopmall 3 4 GOODS = {1:{'name':'iphone8', 'price':6888, 'inventory':30}, 5 2:{'name':'iphoneX', 'price':8388, 'inventory':8}, 6 3:{'name':'ipad mini4', 'price':2888, 'inventory':20}, 7 4:{'name':'MI MIX2', 'price':3288, 'inventory':25}, 8 5:{'name':'MEIZU Pro8', 'price':2488, 'inventory':2}} 9 10 11 if __name__ == "__main__": 12 username = login_module.login() 13 shopmall.purchase(username, GOODS)
4. 用户信息记录文件
1 wayne 123 1999829036 2 kevin 123 20000 3 root shroot123 3000
5. 用户锁定记录文件
1 kevin 2 james