js实现数组去重方法及效率比

2019-11-19 17:35:29

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其上搜索些方法一堆堆的，之所以一遍主要是因自己一之後就忘了其他方法怎麽，就一一下，便做看看哪效率最高，了更好展示效果，我先比好的方法，後面一。（馨提示：下文是了便，一般情下不建在原型上，容易污染全局）

一，通找象性

var n = [14,12,2,2,2,5,32,2,59,5,6,33,12,32,6];Array.prototype.unique1 = function(){ var obj = {},  ary = [],  i= 0,  len = this.length; for(; i<len; i++){  if(!obj[this[i]]){   obj[this[i]] = 1;   ary.push(this[i]);  } } return ary.sort(function(a,b){return a - b});}console.log(n.unique1());

二，通找位置

var n = [14,12,2,2,2,5,32,2,59,5,6,33,12,32,6];Array.prototype.unique2 = function(){ var ary = [],  i= 0,  len = this.length; for(; i<len; i++){  if(ary.indexOf(this[i]) == -1) ary.push(this[i]); } return ary.sort(function(a,b){return a - b});}console.log(n.unique2());

三，跟找位置似，搜索字第一次出的位置是不是跟前位置一

var n = [14,12,2,2,2,5,32,2,59,5,6,33,12,32,6];Array.prototype.unique3 = function(){ var ary = [],  i= 0,  len = this.length; for(; i<len; i++){  if(this.indexOf(this[i]) == i) ary.push(this[i]); } return ary.sort(function(a,b){return a - b});}console.log(n.unique3());

四，比常，先排序，再比前後字是不是相等

var n = [14,12,2,2,2,5,32,2,59,5,6,33,12,32,6];Array.prototype.unique4 = function(){ this.sort(function(a,b){return a - b}); var ary = [],  i= 0,  len = this.length; for(; i<len; i++){  if(this[i] !== this[i-1]) ary.push(this[i]); } return ary;}console.log(n.unique4());

接下是上比少的效率比了，也是本文重，我先生成一函一比

首先生成一一百字的

Array.prototype.unique1 = function(){ var obj = {},  ary = [],  i= 0,  len = this.length; for(; i<len; i++){  if(!obj[this[i]]){   obj[this[i]] = 1;   ary.push(this[i]);  } } return ary.sort(function(a,b){return a - b});}Array.prototype.unique2 = function(){ var ary = [],  i= 0,  len = this.length; for(; i<len; i++){  if(ary.indexOf(this[i]) == -1) ary.push(this[i]); } return ary.sort(function(a,b){return a - b});}Array.prototype.unique3 = function(){ var ary = [],  i= 0,  len = this.length; for(; i<len; i++){  if(this.indexOf(this[i]) == i) ary.push(this[i]); } return ary.sort(function(a,b){return a - b});}Array.prototype.unique4 = function(){ this.sort(function(a,b){return a - b}); var ary = [],  i= 0,  len = this.length; for(; i<len; i++){  if(this[i] !== this[i-1]) ary.push(this[i]); } return ary;}function randomAry (n) { var ary = [],i=0; for(; i<n; i++){  ary.push(Math.ceil(Math.random()*10000)); }  console.log(ary) return ary;}function useTime (fn) { var start = new Date(); fn(); var end = new Date(); console.log('本次函行花了：' + (end - start) + '毫秒');}var ary = randomAry(100), fn1 = function(){ ary.unique1() }, fn2 = function(){ ary.unique2() }, fn3 = function(){ ary.unique3() }, fn4 = function(){ ary.unique4() };useTime(fn1);useTime(fn2);useTime(fn3);useTime(fn4);

果在我的谷歌器

方法一：0毫秒

方法二：1毫秒

方法三：0毫秒

方法四：00毫秒

（嗯，果然代器强大比，不吐槽器了）

看看1000字

Array.prototype.unique1 = function(){ var obj = {},  ary = [],  i= 0,  len = this.length; for(; i<len; i++){  if(!obj[this[i]]){   obj[this[i]] = 1;   ary.push(this[i]);  } } return ary.sort(function(a,b){return a - b});}Array.prototype.unique2 = function(){ var ary = [],  i= 0,  len = this.length; for(; i<len; i++){  if(ary.indexOf(this[i]) == -1) ary.push(this[i]); } return ary.sort(function(a,b){return a - b});}Array.prototype.unique3 = function(){ var ary = [],  i= 0,  len = this.length; for(; i<len; i++){  if(this.indexOf(this[i]) == i) ary.push(this[i]); } return ary.sort(function(a,b){return a - b});}Array.prototype.unique4 = function(){ this.sort(function(a,b){return a - b}); var ary = [],  i= 0,  len = this.length; for(; i<len; i++){  if(this[i] !== this[i-1]) ary.push(this[i]); } return ary;}function randomAry (n) { var ary = [],i=0; for(; i<n; i++){  ary.push(Math.ceil(Math.random()*10000)); }  console.log(ary) return ary;}function useTime (fn) { var start = new Date(); fn(); var end = new Date(); console.log('本次函行花了：' + (end - start) + '毫秒');}var ary = randomAry(1000), fn1 = function(){ ary.unique1() }, fn2 = function(){ ary.unique2() }, fn3 = function(){ ary.unique3() }, fn4 = function(){ ary.unique4() };useTime(fn1);useTime(fn2);useTime(fn3);useTime(fn4);方法一：1-2毫秒方法二：40-50毫秒方法三：40-50毫秒方法四：0-1毫秒看看10000字（大，始吃不消了，等五六秒吧）Array.prototype.unique1 = function(){ var obj = {},  ary = [],  i= 0,  len = this.length; for(; i<len; i++){  if(!obj[this[i]]){   obj[this[i]] = 1;   ary.push(this[i]);  } } return ary.sort(function(a,b){return a - b});}Array.prototype.unique2 = function(){ var ary = [],  i= 0,  len = this.length; for(; i<len; i++){  if(ary.indexOf(this[i]) == -1) ary.push(this[i]); } return ary.sort(function(a,b){return a - b});}Array.prototype.unique3 = function(){ var ary = [],  i= 0,  len = this.length; for(; i<len; i++){  if(this.indexOf(this[i]) == i) ary.push(this[i]); } return ary.sort(function(a,b){return a - b});}Array.prototype.unique4 = function(){ this.sort(function(a,b){return a - b}); var ary = [],  i= 0,  len = this.length; for(; i<len; i++){  if(this[i] !== this[i-1]) ary.push(this[i]); } return ary;}function randomAry (n) { var ary = [],i=0; for(; i<n; i++){  ary.push(Math.ceil(Math.random()*10000)); }  console.log(ary) return ary;}function useTime (fn) { var start = new Date(); fn(); var end = new Date(); console.log('本次函行花了：' + (end - start) + '毫秒');}var ary = randomAry(10000), fn1 = function(){ ary.unique1() }, fn2 = function(){ ary.unique2() }, fn3 = function(){ ary.unique3() }, fn4 = function(){ ary.unique4() };useTime(fn1);useTime(fn2);useTime(fn3);useTime(fn4);

因大，我拿一次，你喜就刷新次比

方法一：10毫秒

方法二：1258毫秒

方法三：2972毫秒

方法四：5毫秒

原本想更大的看看，然後十我的面就奔了。。。了。。。了

然後五，也奔了。。。了。。。了

那就算吧，

反正在一面比，越大，方法一跟方法四按毫秒增，方法二跟方法三效率感人

效率算：4>1>2>3

方法算：先排序，再比前後字是不是相等 > 通找象性 > 通找位置 > 搜索字第一次出的位置是不是跟前位置一

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