js 数组去重复的方法
数组去重复是js中常用的方法，归纳了四种如下：
1. for + indexOf 去重复
1 var arr = [3,5,5,4,1,1,2,3,7,2,5]; 2 var target = []; 3 for(var i=0,len=arr.length;i<len;i++){ 4 if( target.indexOf(arr[i])==-1 ){ 5 target.push(arr[i]); 6 } 7 }; 8 console.log(target);
2. forEach + indexOf 去重复
1 var arr = [3,5,5,4,1,1,2,3,7,2,5]; 2 var target = []; 3 arr.forEach(function(val){ 4 if(this.indexOf(val)==-1){ 5 this.push(val); 6 }; 7 },target); 8 console.log(target);
3.原型对象 prototype + for + indexOf 去重复
1 Array.prototype.quchong = function(){ 2 var target = [] ; 3 for(var i=0,len=this.length;i<len;i++){ 4 if(target.indexOf(this[i])==-1){ 5 target.push(this[i]); 6 } 7 }; 8 return target; 9 }; 10 var arr = [3,5,5,4,1,1,2,3,7,2,5]; 11 console.log(arr.quchong());
4.原型对象 prototype + forEach + indexOf 去重复
1 Array.prototype.quchong = function(){ 2 var target = []; 3 this.forEach(function(val){ 4 if(this.indexOf(val)==-1){ 5 this.push(val); 6 } 7 },target); 8 return target; 9 }; 10 var arr = [3,5,5,4,1,1,2,3,7,2,5]; 11 console.log(arr.quchong());
运行结果：