js中数组排序的三种方法

// 快速排序

var quickSort = function( arr) {

    if(arr.length < 1) { //如果数组就是一项，那么可以直接返回

        return arr;

    }

    var centerIndex = Math. floor(arr.length / 2); //获取数组中间的索引

    var centerValue = arr[centerIndex]; //获取数组中间项

    var left = [], right = [];

    for( var i = 0; i < arr.lenght; i ++){

        if(arr[i] < centerValue){

            left. push(arr[i]);

        } else{

            right. push(arr[i]);

        }

    }

    return quickSort(left). contanct([centerValue], quickSort(right)); //递归调用

}

// 冒泡排序

var bubbleSort = function( arr) {

    var len = arr.length;

    for( var i = 0; i < len; i ++){

        for( var j = 0; i < len - 1 - i; i ++){

            if(arr[j] > arr[j + 1]) { //相邻元素两两对比

                var temp = arr[j + 1]; //元素交换

                arr[j + 1] = arr[j];

                arr[j] = temp;

            }

        }

    }

    return arr;

}

// 插入排序

var insertSort = function( arr) {

    var len = arr.length;

    var preIndex, current;

    for( var i = 1; i < len; i ++){

        preIndex = i - 1;

        current = arr[i];

        while(preIndex >= 0 && arr[preIndex] > current){

            arr[preIndex + 1] = arr[preIndex];

            preIndex --;

        }

        arr[preIndex + 1] = current;

    }

    return arr;

}

//数组去重:

Array.prototype. myUnique = function myUnique(){

    //this是当前要操作的数组

    var obj = {};

    for( var i = 0; i < this.length; i ++){

        var cur = this[i];

        if (obj[cur] == cur){

            this[i] = this[ this.length - 1];

            this.length --;

            i --; //防止数组塌陷

            continue;

        }

        obj[cur] = cur;

    }

    obj = null;

    return this; //为了实现链式写法

};

ary. myUnique(). sort();

ary. myUnique();