sort常见排序

一.升序x-y

<script>
    var a = [5,10,110,45,265,88,9];
    a.sort(function (x, y) {
        return x-y;
    });
    console.log(a);
</script>

二.降序y-x

<script>
    var a = [5,10,110,45,265,88,9];
    a.sort(function (x, y) {
        return y-x;
    });
    console.log(a);
</script>

例：按年龄从低到高排序，年龄相同时按性别排序

<script>
    var a = [
        {
            name:"张琪",
            gender:"男",
            age:18
        },
        {
            name:"李颖",
            gender:"女",
            age:17
        },
        {
            name:"李新宇",
            gender:"男",
            age:18
        },
        {
            name:"王华",
            gender:"女",
            age:18
        },
        {
            name:"刘江",
            gender:"男",
            age:17
        }
    ];
    a.sort(function (x,y) {
        if(x.age!=y.age)
            return x.age-y.age;
        else {
            if(x.gender=="男")
                return 1;
            else
                return -1;
        }
    });
    console.log(a);
</script>

排序结果为：
0: {name: “李颖”, gender: “女”, age: 17}
1: {name: “刘江”, gender: “男”, age: 17}
2: {name: “王华”, gender: “女”, age: 18}
3: {name: “张琪”, gender: “男”, age: 18}
4: {name: “李新宇”, gender: “男”, age: 18}

三.随机排序
var a = [5,10,110,45,265,88,9];
arr.sort( (a,b)=> Math.random()-0.5);

小结：用sort()方法排序时，大部分情况都应该指定比较函数，这个函数给出的是数组中两个元素比较的办法，函数的返回值必须是正负零。你可以自己制定排序规则，这是sort()方法的强大之处。