reverve
数组的倒序方法
Array.prototype.reverse = function(){ //用二分法 for(var i=0;i<this.length/2;i++){ //解构赋值 [this[i],this[this.length-1-i]] = [this[this.length-1-i],this[i]] } return this }
slice
数组截取,不改变原数组,并把截取的新数组返回出去
Array.prototype.Slice =function(n=0,m=this.length){ if(n<=0&&m<0&&this.length+n>this.length+m){ return []; } n<0?n = this.length + n:n; m<0?m = this.length + m:m; m>this.length?m=this.length:m; let res =[]; for(var i=n;i<m;i++){ res[res.length]=this[i]; } return res; }
concat
数组拼接,支持单个参数和数组
Array.prototype.concat=function(){ let res=[]; for(var j=0;j<this.length;j++){ res[res.length]=this[j] } for(var i=0;i<arguments.length;i++){ if({}.toString.call(arguments[i]) === ‘[object Array]‘){ for(var z=0;z<arguments[i].length;z++){ res[res.length]=arguments[i][z] } }else{ res[res.length]=arguments[i] } } return res; }
sort
主要利用冒泡,不传参按照数字第一位排序,传参,a-b升序b-a倒序
Array.prototype.sort=function(compare){ //判断传入的是不是函数 if(typeof compare !== "function"&& compare !== undefined){ throw new Error( " The comparison function must be either a function or undefined" + "at Array.sort (native)" ); } for (var i = 0; i < this.length-1; i++) { for (var j = 0; j < this.length-1-i; j++) { //传入回调函数走这里 if(compare){ //a-b和b-a都是大于0才换位置 if(compare(this[j],this[j+1])>0){ [this[j],this[j+1]] = [this[j+1],this[j]] } //不传回调走这里,按首个数字排序 }else{ if((this[j]+"")[0] - (this[j+1]+"")[0] > 0 ){ [this[j],this[j+1]] = [this[j+1],this[j]] } } } } }
原文地址:https://www.cnblogs.com/bxbxb/p/12150467.html
时间: 2024-10-02 20:29:13