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JavaScript array deduplication/search/insertion/deletion methods

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Release: 2017-10-26 10:06:04
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Array deduplication

Prototype method

//---------------first---------------
 Array.prototype.distinct = function(){
      var arr=[];
      var obj={}; //对象承接
      for(var i=0,len=this.length;i<len;i++){
          if(!obj[this[i]]){
              obj[this[i]]=1;
              arr.push(this[i]);
          }
      }
   return arr;
};
var arr = new Array();
arr.push(1,3,2,4,4,4,5,6,7,8,8,8,9,0);

//--------------second----------------
 Array.prototype.distinct = function(){
    var arr=[];
    for(var i=0,len=this.length;i<len;i++){
      if(this[i]==this[i+1]){
        continue;
      }else{
        arr.push(this[i]);
      }    
    }
 return arr;
};
var arr = new Array();
arr.push(1,3,2,4,4,4,5,6,7,8,8,8,9,0);

//----------------third----------------
Array.prototype.distinct = function(){ 
    for(var i=0,len=this.length;i<len;i++){
      for(var j=i+1;j<=len;j++){
        if(this[i]==this[j]){
          console.log(this[j]);
          this.splice(j,1);
          j--; //得考虑如果删除一个元素,j的值需要减1
          len--;
        }
      }    
    }
  //return this;
};
var arr = new Array();
arr.push("a","b","c","c","b","bb","dd","d","aa","c","bb");
arr.distinct();
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Common method

function removeRepeat(arr){
   var array=[];
   var obj={};
   for(var i=0,len=arr.length;i<len;i++){
      if(!obj[arr[i]]){
        obj[arr[i]]=1;
        array.push(arr[i]);
      }
   }
   return array;
};
var arr = new Array(1,3,2,4,4,4,5,6,7,8,8,8,9,0);
var array = removeRepeat(arr);
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Array search

Sequential search

function SequenceSearch(arr, value){
    var i;
    for(i=0; i<arr.length; i++){
         if(arr[i]==value)
         return i;
    }
    return -1;
}
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Binary search

Binary search elements must be in order. If they are unordered, sorting operation must be performed first

-------------折半查找--------------
function BinarySearch1(arr, value){
    var low, high, mid;
    low = 0;
    high = arr.length-1;
    while(low<=high){
        mid = Math.floor((low+high)/2);
        if(a[mid]==value){
             return mid;
        }
        if(a[mid]>value){
            high = mid-1;
        }
        if(a[mid]<value){
            low = mid+1;
        }
    }
    return -1;
}
-------------递归版本--------------
function BinarySearch2(arr, value){
    var low, high, mid;
    low = 0;
    high = arr.length-1;
    var mid = low+(high-low)/2;
    if(arr[mid]==value){
        return mid;
    }
    if(a[mid]>value){
        return BinarySearch2(arr, value);
    }
    if(a[mid]<value){
        return BinarySearch2(arr, value);
    }
}
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Array insertion

Sequential insertion

//----------------first----------------
function Insert(arr, n, data){
    //若插入数据位置不在表尾
    if (n < arr.length){
        //将要插入位置之后元素依次向后移动一位
        for (var i = seqList.ListLen - 1; i >= n; i--) {
            seqList.ListData[i + 1] = seqList.ListData[i];
        }
    }
    //将数据插入到位置为n的位置并将数组的长度加1
    seqList.ListData[n-1] = data;
    seqList.ListLen++;
    return true;
}

//----------------second----------------
function  aa(arr, val) {
    for (var i = 0; i <arr.length; i++) {
        if (arr[i] == val) return i;
    }
    return -1;
};
function bb(arr, val) {
    var index =arr.indexOf(val);
    if (index > -1) {
    arr.splice(index, 1);
    }
};
var emp = [&#39;abs&#39;,&#39;dsf&#39;,&#39;sdf&#39;,&#39;fd&#39;]
bb(emp, &#39;fd&#39;);
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Array deletion

function Delete(arr, n){
    //判断数组是否为空
    if (seqList.ListLen == 0) return false;
    //判断n的位置是否合法
    if (n < 1 || n > seqList.ListLen) return false;
    //如果删除不是最后位置
    if (n < seqList.ListLen) {
        //将删除位置后继元素依次前移
        for (int i = n; i < seqList.ListLen; i++) {
            seqList.ListData[i-1] = seqList.ListData[i];
        }
    }
    //表长减1
    seqList.ListLen--;
    return true;
}
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