join方法 把数值转换为字符串,可以改变连接符号
var nums= [2,3,4,5,9];
var str = nums.join();
console.log(str); //输出结果 2,3,4,5,9
var num= ["a","b","c","d"];
var str1 = num.join("-"); //连接符号为 -
var str2 = num.join(""); // 连接符号为空格
console.log(str1); //输出结果 a-b-c-d
console.log(str2); //输出结果 abcd
reverse方法 将数组翻转过来
nums.reverse();
console.log(nums); //输出结果 [9, 5, 4, 3, 2]
var strs=["a","b","c","d"];
var newstr = strs.reverse().join(""); //将数组翻转过来且改变连接方式
console.log(newstr); //输出结果 dcba
sort方法 将数组重新排序
var t = ["z","t","q","p","w"];
var t1 = ["9","66","23","88","13","15"];
var t2 = ["9","66","23","88","13","15"];
console.log(t.sort()); //输出结果 ["p", "q", "t", "w", "z"]
//console.log(t1.sort());
t1.sort(function(a,b){return b-a}); //重点:当数组为数字的时候,sort方法无法按我们想要的来进行排序,它只能按第一个数字的大小排序,
因此我们要加入一个匿名函数在里面,填写两个参数
t2.sort(function(a,b){return a-b});
console.log(t1); //输出结果 ["88", "66", "23", "15", "13", "9"]
console.log(t2); //输出结果 ["9", "13", "15", "23", "66", "88"]