<!DOCTYPE html> 
<html lang="en"> 
  <head> 
    <meta charset="utf-8"> 
    <title>數(shù)組操作</title> 
  </head> 
  <body> 
  <script type="text/javascript"> 
    var arr=[3,1,2,2,1,3,1]; 
    var sum=[]; 
    var res=[]; 
    var count=0; 
    var temp; 
    for(var i=0;i<arr.length;i++){ 
      if(res.indexOf(arr[i])==-1){ 
        res.push(arr[i]); 
      } 
    } 
    for(var i=0;i<res.length;i++){ 
      for(var j=0;j<arr.length;j++){ 
        if(arr[j]==res[i]){ 
          count++; 
        } 
      } 
      sum.push(count); 
      count=0; 
    } 
    console.log(res);//[3,1,2] 
    for(var i=0;i<res.length;i++){ 
      var str=(sum[i]%2==0)?"偶數(shù)":"奇數(shù)"; 
      console.log(res[i]+"出現(xiàn)了"+sum[i]+"次"); 
      console.log(res[i]+"出現(xiàn)了"+str+"次"); 
    } 
  </script> 
  </body> 
</html>

阿里筆試-數(shù)組操作-找出兩個(gè)數(shù)組中不同的元素

<script type="text/javascript"> 
  function diff(arr1,arr2){ 
  var ress = []; 
  var arr = arr1.concat(arr2); 
  for(var i=0,len=arr.length;i<len;i++){ 
     if((arr1.indexOf(arr[i])>=0 && arr2.indexOf(arr[i])<0) || (arr1.indexOf(arr[i])<0 && arr2.indexOf(arr[i])>=0)){ 
        ress.push(arr[i]); 
     } 
  } 
  return ress; 
} 
var arr1 = [1,2,3,5,7,6]; 
var arr2 = [1,2,5]; 
var res = diff(arr1,arr2); 
console.log(res);//[3, 7, 6] 
</script>

數(shù)組去重

方法1

<!DOCTYPE html> 
<html lang="en"> 
  <head> 
    <meta charset="utf-8"> 
    <title>數(shù)組去重01</title> 
  </head> 
  <body> 
  <script type="text/javascript"> 
  //給數(shù)組原型添加方法 
    Array.prototype.unique = function(){ 
      var arr = []; 
      for(var i=0,i=this.length;i<len;i++){ 
        if(arr.indexOf(this[i]) == -1){ 
          arr.push(this[i]); 
        } 
      } 
      return arr; 
    }; 
    console.log([1,2,3,2,5,6,3].unique());//[1, 2, 3, 5, 6] 
  </script> 
  </body> 
</html>

方法2

<!DOCTYPE html> 
<html lang="en"> 
  <head> 
    <meta charset="utf-8"> 
    <title>數(shù)組去重02</title> 
  </head> 
  <body> 
  <script type="text/javascript"> 
    Array.prototype.unique = function(){ 
    var n = {}, 
        r=[]; //n為哈希表，r為臨時(shí)數(shù)組 
    for(var i = 0; i < this.length; i++) //遍歷當(dāng)前數(shù)組 
    { 
      if (!n[this[i]]) //如果hash表中沒(méi)有當(dāng)前項(xiàng) 
      { 
        n[this[i]] = true; //存入哈希表 
        r.push(this[i]); //把當(dāng)前數(shù)組的當(dāng)前項(xiàng)push到臨時(shí)數(shù)組里面 
      } 
    } 
    return r; 
  } 
  console.log([1,2,3,2,5,6,3].unique());//[1, 2, 3, 5, 6] 
  </script> 
  </body> 
</html>

方法3

<!DOCTYPE html> 
<html lang="en"> 
  <head> 
    <meta charset="utf-8"> 
    <title>數(shù)組去重</title> 
  </head> 
  <body> 
  <script type="text/javascript"> 
    Array.prototype.unique = function(){ 
      var arr = [this[0]];//結(jié)果數(shù)組 
      for(var i=1;i<this.length;i++){//從第二項(xiàng)開(kāi)始遍歷 
        if(this.indexOf(this[i]) == i){ 
      //如果當(dāng)前數(shù)組的第i項(xiàng)在當(dāng)前數(shù)組中第一次出現(xiàn)的位置不是i，那么表示第i項(xiàng)是重復(fù)的，忽略掉。否則存入結(jié)果數(shù)組 
          arr.push(this[i]); 
        } 
      } 
      return arr; 
    } 
    console.log([1,2,3,4,2,3,4].unique());// [1, 2, 3, 4] 
  </script> 
  </body> 
</html>

方法4

<!DOCTYPE html> 
<html> 
<head> 
  <meta charset="utf-8"> 
  <meta http-equiv="X-UA-Compatible" content="IE=edge"> 
  <title>filter</title> 
  <link rel="stylesheet" href=""> 
</head> 
<body> 
<script type="text/javascript"> 
var arr = [4,5,3,2,3,4,5,1]; 
function fn(num){ 
  var res = num.filter(function(item,index,array){ 
    return num.indexOf(item) === index;//num.indexOf(item)將會(huì)返回元素在數(shù)組第一次出現(xiàn)的位置 
    //對(duì)于多次出現(xiàn)的元素，除第一次外，其他情況都返回false 
  }); 
  return res; 
} 
console.log(fn(arr));//[4, 5, 3, 2, 1] 
</script> 
</body> 
</html>

方法5

<!DOCTYPE html> 
<html> 
<head> 
  <meta charset="utf-8"> 
  <meta http-equiv="X-UA-Compatible" content="IE=edge"> 
  <title>Object 對(duì)象來(lái)當(dāng)做哈希表</title> 
  <link rel="stylesheet" href=""> 
</head> 
<body> 
<script type="text/javascript"> 
function unique(a) { 
 var obj = {}; 
 return a.filter(function(item) {//filter會(huì)返回true的項(xiàng)組成的成員 
  return obj.hasOwnProperty(item) ? false : (obj[item] = true); 
 }); 
} 
 
var a = [1, 1, 3, 2, 1, 2, 4]; 
var res = unique(a); 
console.log(res); // [1, 3, 2, 4] 
</script> 
</body> 
</html>

以上就是小編為大家?guī)?lái)的js數(shù)組操作方法總結(jié)(必看篇)全部?jī)?nèi)容了，希望大家多多支持腳本之家~

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