// 19. ["a","b","c","d","e","f","g"]
// 获取索引3-5的元素，包含5号元素
var arr19 = ["a", "b", "c", "d", "e", "f", "g"];
var arr20 = arr19.slice(3, 6);
console.log(arr20); // ["d","e","f"]
console.log(arr19); //["a", "b", "c", "d", "e", "f", "g"]
// 21. [1,2,5,8,9,7,6]
// 删除8，9两个元素
let arr21 = [1, 2, 5, 8, 9, 7, 6];
let arr22 = arr21.splice(3, 2);
console.log(arr21); // [1,2,5,7,6]
console.log(arr22); // [8,9]
