一.商品买卖程序：
要求：1.启动程序后，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码购买商品
3.用户购买商品后，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
初始版本：
1 goods= [[‘apple‘, 6], [‘banana‘, 3], [‘orange‘, 4]] 2 shopping_cart = [] 3 4 salary = int(input("Salary:")) 5 while True: 6 for good in goods: 7 print(goods.index(good)+1,". ", end="") 8 for value in good: 9 print(value,‘ ‘, end="") 10 print() 11 i = int(input(‘Which one do you want to buy?‘)) 12 if goods[i-1][1] > salary: 13 print("You don‘t have enough money!") 14 break 15 else: 16 salary = salary - goods[i-1][1] 17 shopping_cart.append(goods[i-1]) 18 print(‘You balance: ‘,salary) 19 print(‘You shopping cart has: ‘,shopping_cart)
以下是优化版本：
1 goods= [[‘apple‘, 6], [‘banana‘, 3], [‘orange‘, 4]] 2 shopping_cart = [] 3 4 salary = input("Salary:") 5 if salary.isdigit(): 6 salary = int(salary) 7 while True: 8 for index, good in enumerate(goods): 9 print(index+1, ‘. ‘, good) 10 user_choice = input(‘Which one do you want to buy?‘) 11 if user_choice.isdigit(): 12 user_choice = int(user_choice) - 1 13 if user_choice < len(goods) and user_choice >= 0: 14 p_items = goods[user_choice] 15 if p_items[1] <= salary: 16 shopping_cart.append(p_items) 17 salary -= p_items[1] 18 print("Add %s into shopping cart, your current balance is \033[31;1m%s\033[0m"%(p_items, salary)) 19 else: 20 print("\033[41;1mYou banlance only left [%s].\033[0m"%(salary)) 21 else: 22 print("Invalid option!") 23 elif user_choice == ‘q‘: 24 for i in shopping_cart: 25 print(i) 26 print("\033[31;1mYou banlance only left [%s].\033[0m"%(salary)) 27 exit() 28 else: 29 print("Invalid option!")
优化的地方有：
a. 5，11行增加了对输入字符是否是纯数字进行判断，在判断为是纯数字后，将其强制转为int类型；
若是字母q，则打印购买的物品以及剩余的工资并退出，同时其余输入均判为非法字符；
b. 使用enumerate()得到每个元素的具体位置；
c. 13行判断输入的字符是否在给定范围内；
d. 在18,20行使用 \033[31;1m()\033[0m 将()中的内容显示高亮；
e. 这里使用exit(0退出程序
以下是进一步优化版本：
优化的内容：
用户入口：1.商品信息被存在文件内； 2.已购商品，余额记录；
商家入口：1.可添加商品，修改商品的价格。
1 import time 2 3 seller = [‘seller‘, 123456] 4 buyer = [‘buyer‘, 112233] 5 6 current = input("seller or buyer?") 7 if current == "seller": 8 username = input(‘Username: ‘) 9 password = input(‘Password: ‘) 10 if password.isdigit(): 11 password = int(password) 12 if username == seller[0] and password == seller[1]: 13 print("log in......") 14 time.sleep(5) 15 with open("f_goods", "r") as f1: 16 goods = eval(f1.read()) 17 for index, good in enumerate(goods): 18 print(index + 1, ‘. ‘, good) 19 while True: 20 choice = input("change or add?") 21 if choice == "change": 22 seller_choice = input("Which one do you want to change?") 23 if seller_choice.isdigit(): 24 seller_choice = int(seller_choice) - 1 25 if seller_choice < len(goods) and seller_choice >= 0: # 判断商家的选择是否在目前所有商品的范围内 26 choice = input("name or price?") 27 if choice == ‘goods‘: # 修改货物的名称 28 g_item = input("Good name:") 29 goods[seller_choice][0] = g_item 30 elif choice == ‘price‘: # 修改货物的价格 31 p_item = input("Good price:") 32 if p_item.isdigit(): 33 goods[seller_choice][1] = int(p_item) 34 elif choice == ‘q‘: 35 exit() 36 else: 37 print("\033[46;1mInvalid option!\033[0m") 38 with open("f_goods", "w") as f2: #在文件中又以可读的方式打开了f_goods 39 f2.write(str(goods)) 40 elif choice == "add": 41 good_name = input("Goods name:") 42 good_price = input("Goods price:") 43 if good_price.isdigit(): 44 list = [good_name, int(good_price)] 45 goods.append(list) 46 with open("f_goods", "w") as f2: 47 f2.write(str(goods)) 48 elif choice == ‘q‘: 49 exit() 50 else: 51 print("\033[41;1mWrong username or password!\033[0m") 52 else: 53 print("\033[38;1mInvalid option!\033[0m") 54 55 56 elif current == "buyer": 57 username = input(‘Username: ‘) 58 password = input(‘Password: ‘) 59 if password.isdigit(): 60 password = int(password) 61 if username == buyer[0] and password == buyer[1]: 62 print("log in......") 63 time.sleep(5) 64 with open("f_goods", "r") as f1, open("f_cart", "r") as f2: 65 goods = eval(f1.read()) 66 cart_info = eval(f2.read()) 67 for index, good in enumerate(goods): 68 print(index + 1, ‘. ‘, good) 69 banlance = cart_info["banlance"] 70 shopping_cart = cart_info["shopping_cart"] 71 print("Banlance:", banlance) 72 while True: 73 user_choice = input(‘Which one do you want to buy?‘) 74 if user_choice.isdigit(): 75 user_choice = int(user_choice) - 1 76 if user_choice < len(goods) and user_choice >= 0: 77 p_items = goods[user_choice] 78 if p_items[1] <= banlance: 79 shopping_cart.append(p_items) 80 banlance -= p_items[1] 81 print("Add %s into shopping cart, your current balance is \033[31;1m%s\033[0m" % ( 82 p_items, banlance)) 83 else: 84 print("\033[41;1mYou banlance only left [%s].\033[0m" % (banlance)) 85 else: 86 print("Invalid option!") 87 elif user_choice == ‘q‘: 88 for i in shopping_cart: 89 print(i) 90 print("\033[31;1mYou banlance only left [%s].\033[0m" % (banlance)) 91 cart_info["banlance"] = banlance 92 cart_info["shopping_cart"] = shopping_cart 93 with open("f_cart", "w") as f3: 94 f3.write(str(cart_info)) 95 exit() 96 else: 97 print("Invalid option!") 98 99 else: 100 print("Invalid option!") 101 102 #用到的文件 103 f_goods = [[‘banana‘, 3], [‘orange‘, 4], [‘apple‘, 5], [‘sweets‘, 20]] 104 f_cart = {‘shopping_cart‘: [], ‘banlance‘: 100} #初始余额为100元
这里还可以进一步优化，比如进行代码的重构，增添用户入口的清空购物车以及充值功能，以及商家入口的删除商品功能等。
二.多级菜单程序
1 solar_system = {‘_earth‘: {‘_sky‘: {‘bird‘: ‘fly‘}, 2 ‘_ocean‘: {}, 3 ‘_mountain‘: {} 4 }, 5 ‘_moon‘: None, 6 ‘_mars‘:{‘mars‘: {}} 7 } 8 9 exit_flag = True 10 while exit_flag: 11 for key1 in solar_system.keys(): 12 print(key1) 13 choice1 = input("Which one would you want to watch?") 14 if choice1 in solar_system.keys(): 15 if solar_system[choice1]: 16 for key2 in solar_system[choice1].keys(): 17 print(key2) 18 choice2 = input("Which one would you want to watch?") 19 if choice2 in solar_system[choice1].keys(): 20 if solar_system[choice1][choice2]: 21 for key3 in solar_system[choice1][choice2].keys(): 22 print(key3) 23 choice3 = input("Would you want you exit?") 24 if choice3 == ‘q‘: 25 exit_flag = False 26 else: 27 print("\033[41;1mInvalid input!\033[0m") 28 else: 29 print("\033[41;1mNot exit!\033[0m") 30 elif choice1 == ‘q‘: 31 exit_flag = False 32 else: 33 print("\033[41;1mInvalid input!\033[0m") 34 else: 35 print("\033[41;1mNot exit!\033[0m") 36 elif choice1 == ‘q‘: 37 exit_flag = False 38 else: 39 print("\033[41;1mInvalid input!\033[0m")
一层一层好复杂，并且还有好多弊端，比如，各下层的技术不同，无法处理字符串等。
