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js实现数组去重方法及效率?Ρ?

时间：2021-02-27 14:29:57 | 栏目：JavaScript代码 | 点击：次

其???W上搜索?@些方法一堆堆的，之所以????一遍主要是因??自己??T一?N之後就忘了其他方法怎麽???F，就??一????Y一下，?便做???y?看看哪??效率最高，??了更好展示效果，我??先??Y?J??比?^好的方法，後面?y一?y?。（?剀疤崾荆合挛男}是??了?便，一般情?r下不建?h??在原型上，容易污染全局）

一，通?^?ふ?ο?傩?

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?^?ふ?到M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?ふ?到M位置?似，搜索?底值谝淮纬霈F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????底质遣皇窍嗟?

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?硎蔷W上比?^少的效率比?^了，也是本文重?c，我??先生成一????r函?到y一比?^

首先生成一??一百?底值?到M

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?颠\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);

?Y果在我的谷歌?g?[器?l?F

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?F代?g?[器强大?o比，不吐槽?f?g?[器了）

看看1000???底?

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?颠\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???底郑?????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?颠\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?g就刷新?状伪容^?h

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?o更大的???看看，然後十?f??我的?面就奔?⒘恕！！?⒘恕！！Ａ?

然後??五?f??，也奔?⒘恕！！?⒘恕！！Ａ?

那就算吧，

反正在一?f??????Y面?Ρ龋????越大，方法一跟方法四按毫秒?f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????底质遣皇窍嗟? > 通?^?ふ?ο?傩? > 通?^?ふ?到M位置 > 搜索?底值谝淮纬霈F的位置是不是跟??前位置一??

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