4可以随时退出，退出时，打印购买商品和余额
shopping_list=[] list=[ ('Iphone',5800), ('Mac Pro',9800), ('Bike',800), ('Watch',10600), ('Coffee',31), ('Alex Python',120) ] salary=input('please enter your salary;') if salary.isdigit():#大体意思是输入的是数字 salary=int(salary )#转成数字 while True: for index,i in enumerate (list):#index是下标 从列表第一个开始循环 print(index ,i) choose=input('你想要买什么==>:') if choose .isdigit(): choose =int(choose) if choose <len(list) and choose>=0: a=list[choose]# a表示要购买的那个商品的位置 if a[1]<=salary: #a【1】表示要购买的商品的价格 a表示商品`1 salary=salary-a[1] shopping_list.append(a) print('add %s your shopping_list,并且剩下%s工资' %(a,salary)) else: print('你还剩下%s工资 买个屁 啊！！！'%salary ) else: print('product code [%s] is not exist!'%choose ) elif choose =='q': print('--------shopping list------') for p in shopping_list: print(p) print('add %s your shopping_list,并且剩下%s工资' %(a,salary)) exit() else: print('错误选项') else: print('请输入数字：')老话；背单词 句式
