// 数组
const arr: (number | string)[] = [1, "2", 3];
const stringArr: string[] = ["a", "b", "c"];
const undefinedArr: undefined[] = [undefined];

// type alias 类型别名
type User = { name: string; age: number };

class Teacher1 {
  name: string;
  age: number;
}

const objectArr: Teacher1[] = [
  new Teacher1(),
  {
    name: "dell",
    age: 28,
  },
];

// 元组 tuple
const teacherInfo: [string, string, number] = ["Dell", "male", 18];
// 在读取 csv 文件时可以用到元组数据结构
const teacherList: [string, string, number][] = [
  ["dell", "male", 19],
  ["sun", "female", 26],
  ["jeny", "female", 38],
];