程序讲解： 商品列表是动态的，可能随时增加，减少，所以不能写死 Step1：打印商品列表 方式1 product_list = [ ('Iphone',5800), ('Mac Pro',9800), ('Bike',800), ('Watch',10600), ('Coffee',31), ('Alex Python',120), ] 工资只输入一次，所以放循环外面 salary = input("Input your salary: ") if salary.isdigit(): salary = int(salary) while True: for item in product_list: print(product_list.index(item), item) break 方式2 不通过下标，一个更直接的方法 product_list = [ ('Iphone',5800), ('Mac Pro',9800), ('Bike',800), ('Watch',10600), ('Coffee',31), ('Alex Python',120), ] salary = input("Input your salary: ") if salary.isdigit(): salary = int(salary) while True: for index, item in enumerate(product_list): print(index, item) break 1. 关于 enumerate >>> a = [1,2,3] >>> for i in enumerate(a):print(i) ... (0, 1) (1, 2) (2, 3) 每一个 i 都变成了 一个元组 第一个是小标，第二个是数据本身 enumerate 做的就是 取出了 列表的下标 Step2：根据用户选择做判断 product_list = [ ('Iphone',5800), ('Mac Pro',9800), ('Bike',800), ('Watch',10600), ('Coffee',31), ('Alex Python',120), ] shopping_list = [] salary = input("Input your salary: ") if salary.isdigit(): salary = int(salary) while True: for index, item in enumerate(product_list): print(index, item) user_choice = input("选择要买嘛？>>>:") if user_choice.isdigit(): user_choice = int(user_choice) if user_choice < len(product_list) and user_choice >= 0: # 接下来判断钱是否够用 p_item = product_list[user_choice] if p_item[1] <= salary: # 买的起 shopping_list.append(p_item) salary -= p_item[1] print("Added %s into shopping cart, your current balance is %s" %(p_item, salary)) elif user_choice == 'q': print('exit....') else: print("invalid option") 1. 如果想给结果变个颜色，红色 31，绿色 32 print("Added %s into shopping cart, your current balance is 33[31;1m%s 33[0m" %(p_item, salary)) 这个就是死记,后面 033[0m 一定要关闭 product_list = [ ('Iphone',5800), ('Mac Pro',9800), ('Bike',800), ('Watch',10600), ('Coffee',31), ('Alex Python',120), ] shopping_list = [] salary = input("Input your salary: ") if salary.isdigit(): salary = int(salary) while True: for index, item in enumerate(product_list): print(index, item) user_choice = input("选择要买嘛？>>>:") if user_choice.isdigit(): user_choice = int(user_choice) if user_choice < len(product_list) and user_choice >= 0: # 接下来判断钱是否够用 p_item = product_list[user_choice] if p_item[1] <= salary: # 买的起 shopping_list.append(p_item) salary -= p_item[1] print("Added %s into shopping cart, your current balance is 33[31;1m%s 33[0m" %(p_item, salary)) elif user_choice == 'q': print('exit....') else: print("invalid option") 2. 这是能买得起的情况，如果买不起呢？ product_list = [ ('Iphone',5800), ('Mac Pro',9800), ('Bike',800), ('Watch',10600), ('Coffee',31), ('Alex Python',120), ] shopping_list = [] salary = input("Input your salary: ") if salary.isdigit(): salary = int(salary) while True: for index, item in enumerate(product_list): print(index, item) user_choice = input("选择要买嘛？>>>:") if user_choice.isdigit(): user_choice = int(user_choice) if user_choice < len(product_list) and user_choice >= 0: # 接下来判断钱是否够用 p_item = product_list[user_choice] if p_item[1] <= salary: # 买的起 shopping_list.append(p_item) salary -= p_item[1] print("Added %s into shopping cart, your current balance is 33[31;1m%s 33[0m" %(p_item, salary)) else: print(" 33[41;1m你的余额只剩[%s]啦，还买个毛线 33[0m"%salary) 2-1 31 和 41 的区别 32 是绿色，42 就是背景是绿色 elif user_choice == 'q': print('exit....') else: print("invalid option") 3. 如果现在想退出了，打印已经买的产品 product_list = [ ('Iphone',5800), ('Mac Pro',9800), ('Bike',800), ('Watch',10600), ('Coffee',31), ('Alex Python',120), ] shopping_list = [] salary = input("Input your salary: ") if salary.isdigit(): salary = int(salary) while True: for index, item in enumerate(product_list): print(index, item) user_choice = input("选择要买嘛？>>>:") if user_choice.isdigit(): user_choice = int(user_choice) if user_choice < len(product_list) and user_choice >= 0: # 接下来判断钱是否够用 p_item = product_list[user_choice] if p_item[1] <= salary: # 买的起 shopping_list.append(p_item) salary -= p_item[1] print("Added %s into shopping cart, your current balance is 33[31;1m%s 33[0m" %(p_item, salary)) else: print(" 33[41;1m你的余额只剩[%s]啦，还买个毛线 33[0m"%salary) elif user_choice == 'q': print("-------shopping list--------") for p in shopping_list: print(p) 3-1. 最后是退出，用exit() print("Your current balance:",salary) exit() else: print("invalid option") 4. 现在可以输入 6 应该如何处理？ product_list = [ ('Iphone',5800), ('Mac Pro',9800), ('Bike',800), ('Watch',10600), ('Coffee',31), ('Alex Python',120), ] shopping_list = [] salary = input("Input your salary: ") # 输入工资，判断是不是数字 if salary.isdigit(): # 如果是数字 # 如果输入的工资不是数字，就退出了，可以加 else 判断 salary = int(salary) # 将其int while True: for index, item in enumerate(product_list): print(index, item) user_choice = input("选择要买嘛？>>>:") if user_choice.isdigit(): user_choice = int(user_choice) if user_choice < len(product_list) and user_choice >= 0: # 接下来判断钱是否够用 p_item = product_list[user_choice] if p_item[1] <= salary: # 买的起 shopping_list.append(p_item) salary -= p_item[1] print("Added %s into shopping cart, your current balance is 33[31;1m%s 33[0m" %(p_item, salary)) else: print(" 33[41;1m你的余额只剩[%s]啦，还买个毛线 33[0m"%salary) # 4-1 如果输入的数字不在范围内 else: print("product code [%s] is not exist!"% user_choice) elif user_choice == 'q': print("-------shopping list--------") for p in shopping_list: print(p) print("Your current balance:",salary) exit() else: print("invalid option")