一、前言：

我们在实际工作中，或者在面试找工作时，都会用到或者被问到一个问题，那就是“数组如何去重”。是的，这个问题有很多种解决方案，看看下面的十种方式吧！

二、数组去重方式大汇总：

Methods 1: 思路：定义一个新数组，并存放原数组的第一个元素，然后将元素组一一和新数组的元素对比，若不同则存放在新数组中。

  1. 		function unique(arr){
  2. 			var res = [arr[0]];
  3. 			for(var i=1; i<arr.length; i++){
  4. 				var repeat = false;
  5. 				for(var j=0; j<res.length; j++){
  6. 					if(arr[i] === res[j]){
  7. 						repeat = true;
  8. 						break;
  9. 					}
  10. 				}
  11.  
  12. 				if(!repeat){
  13. 					res.push(arr[i]);
  14. 				}
  15. 			}
  16. 			return res;
  17. 		}
  18. 		console.log('------------方法一---------------');
  19. 		console.log(unique([1,1,2,3,5,3,1,5,6,7,4]));
  20.

Methods 2: 思路：先将原数组排序，在与相邻的进行比较，如果不同则存入新数组。

  1. 		function unique2(arr){
  2. 			var arr2 = arr.sort();
  3. 			var res = [arr2[0]];
  4. 			for(var i=1; i<arr2.length; i++){
  5. 				if(arr2[i] !== res[res.length-1]){
  6. 					res.push(arr2[i]);
  7. 				}
  8. 			}
  9.  
  10. 			return res;
  11. 		}
  12. 		console.log('------------方法二---------------');
  13. 		console.log(unique2([1,1,2,3,5,3,1,5,6,7,4]));
  14.

Methods 3: 利用对象属性存在的特性，如果没有该属性则存入新数组。

  1. 		function unique3(arr){
  2. 			var res = [];
  3. 			var obj = {};
  4. 			for(var i=0; i<arr.length; i++){
  5. 				if( !obj[arr[i]] ){
  6. 					obj[arr[i]] = 1;
  7. 					res.push(arr[i]);
  8. 				}
  9. 			}
  10.  
  11. 			return res;
  12. 		}
  13. 		console.log('------------方法三---------------');
  14. 		console.log(unique3([1,1,2,3,5,3,1,5,6,7,4]));
  15.

Methods 4: 利用数组的indexOf下标属性来查询。

  1. 		function unique4(arr){
  2. 			var res = [];
  3. 			for(var i=0; i<arr.length; i++){
  4. 				if(res.indexOf(arr[i]) == -1){
  5. 					res.push(arr[i]);
  6. 				}
  7. 			}
  8.  
  9. 			return res;
  10. 		}
  11. 		console.log('------------方法四---------------');
  12. 		console.log(unique4([1,1,2,3,5,3,1,5,6,7,4]));
  13.

Methods 5: 利用数组原型对象上的includes方法。

  1. 		function unique5(arr){
  2. 			var res = [];
  3.  
  4. 			for(var i=0; i<arr.length; i++){
  5. 				if( !res.includes(arr[i]) ){ // 如果res新数组包含当前循环item
  6. 					res.push(arr[i]);
  7. 				}
  8. 			}
  9.  
  10. 			return res;
  11. 		}
  12. 		console.log('------------方法五---------------');
  13. 		console.log(unique5([1,1,2,3,5,3,1,5,6,7,4]));
  14.

Methods 6: 利用数组原型对象上的 filter 和 includes方法。

  1. 		function unique6(arr){
  2. 			var res = [];
  3.  
  4. 			res = arr.filter(function(item){
  5. 			  return res.includes(item) ? '' : res.push(item);
  6. 			});
  7.  
  8. 			return res;
  9. 		}
  10. 		console.log('------------方法六---------------');
  11. 		console.log(unique6([1,1,2,3,5,3,1,5,6,7,4]));
  12.

Methods 7: 利用数组原型对象上的 forEach 和 includes方法。

  1. 		function unique7(arr){
  2. 			var res = [];
  3.  
  4. 			arr.forEach(function(item){
  5. 			  res.includes(item) ? '' : res.push(item);
  6. 			});
  7.  
  8. 			return res;
  9. 		}
  10. 		console.log('------------方法七---------------');
  11. 		console.log(unique7([1,1,2,3,5,3,1,5,6,7,4]));
  12.

Methods 8: 利用数组原型对象上的 splice 方法。

  1. 		function unique8(arr){
  2. 			var i,
  3. 				j,
  4. 				len = arr.length;
  5.  
  6. 			for(i = 0; i < len; i++){
  7. 		        for(j = i + 1; j < len; j++){
  8. 		            if(arr[i] == arr[j]){
  9. 		                arr.splice(j,1);
  10. 		                len--;
  11. 		                j--;
  12. 		            }
  13. 		        }
  14. 		    }
  15.  
  16. 			return arr;
  17. 		}
  18. 		console.log('------------方法八---------------');
  19. 		console.log(unique8([1,1,2,3,5,3,1,5,6,7,4]));
  20.

Methods 9: 利用数组原型对象上的 lastIndexOf 方法。

  1. 		function unique9(arr){
  2. 			var res = [];
  3.  
  4. 			for(var i=0; i<arr.length; i++){
  5. 				res.lastIndexOf(arr[i]) !== -1 ? '' : res.push(arr[i]);
  6. 			}
  7.  
  8. 			return res;
  9. 		}
  10. 		console.log('------------方法九---------------');
  11. 		console.log(unique9([1,1,2,3,5,3,1,5,6,7,4]));
  12.

Methods 10: 利用 ES6的set 方法。

  1. 		function unique10(arr){
  2. 			//Set数据结构，它类似于数组，其成员的值都是唯一的
  3. 			return Array.from(new Set(arr)); // 利用Array.from将Set结构转换成数组
  4. 		}
  5. 		console.log('------------方法十---------------');
  6. 		console.log(unique10([1,1,2,3,5,3,1,5,6,7,4]));
  7.

三、其他：

有意思的是，当我把数组的长度变得很大的时候（如下所示），测试了一下不同方法的执行时间长短，会发现方法三、四、五、六、七相对来说会更有优势，而方法八的执行速度似乎一直垫底。你也可以在你本地跑一下试试！

  1. 	//测试用的超大数组
  2. 	var arr = [1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3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,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6,7,4,1,1,2,3,5,3,1,5,6];
  3.  
  4. 	//这里只是举例方法三（如果你把所有方法放在一起测试，会更直观的看到执行时间的差异）
  5. 	var time3 = new Date().getTime();
  6. 	function unique3(arr){
  7. 		var res = [];
  8. 		var obj = {};
  9. 		for(var i=0; i<arr.length; i++){
  10. 			if( !obj[arr[i]] ){
  11. 				obj[arr[i]] = 1;
  12. 				res.push(arr[i]);
  13. 			}
  14. 		}
  15.  
  16. 		return res;
  17. 	}
  18. 	console.log('------------方法三---------------');
  19. 	console.log( unique3(arr) );
  20. 	console.log('3所花时间： ' + (new Date().getTime() - time3));

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