CODEWITHSUNDEEP
javascriptjqueryhtmlarrays
Sathya
Sathya

Reputation: 1734

How to get index of all occurrence of the same value in an Array?

I have two arrays like arr1, arr2. Each array having different kind of values. In array one i have repeated some values in multiple times. How can i get same value index and value? Also, how to get array two values from array one same value index?

var arr1 = [100, 200, 100, 300, 600, 200];
var arr2 = [1, 2, 3, 4, 5, 6];

For example, If my custom value is 200. arr1 result will be [1, 5]. How to get arr2 value like [2, 6].

Upvotes: 3

Views: 2519

Answers (5)

e11438
e11438

Reputation: 894

One way of doing this is go through the array 1 and once find your custom value

  • Put that index into one array
  • Get value from array 2 in that index and put it to another array

Here is the code

    var arr1 = [100, 200, 100, 300, 600, 200];
    var arr2 = [1, 2, 3, 4, 5, 6];
    var index=[];
    var result=[];

    var customValue=200;

    for(var i=0;i<arr1.length;i++){
      if(arr1[i]==customValue){
        result.push(arr2[i]);
        index.push(i);
      }
    }
    console.log(index);
    console.log(result);

Upvotes: 0

Joseph
Joseph

Reputation: 692

var arr1 = [100, 200, 100, 300, 600, 200];
var obj={};
for(var iloop=0; iloop< arr1.length; iloop++){
   if(obj[ arr1[iloop] ]){
     obj[ arr1[iloop] ].push(iloop) ;
   }else{
     obj[ arr1[iloop] ]  = [iloop];
   }
}

for(var k in obj){
  if(obj[k] && obj[k].length>1){
    console.log(k, obj[k])
  }
}

Upvotes: 2

Nina Scholz
Nina Scholz

Reputation: 386560

I suggest to use Array#filter with the target array and return true (later also the value) if the element of array1 with the same index is equal to the search value.

The filter() method creates a new array with all elements that pass the test implemented by the provided function.

var arr1 = [100, 200, 100, 300, 600, 200],
    arr2 = [1, 2, 3, 4, 5, 6];

function getMappedValues(array1, array2, value) {
    return array2.filter(function (_, i) {
        return array1[i] === value;
    });
}

document.write('<pre>' + JSON.stringify(getMappedValues(arr1, arr2, 200), 0, 4) + '</pre>');

Upvotes: 1

gurvinder372
gurvinder372

Reputation: 68393

try

  function findIndexes(arr, value, fromIndex, indexes)
    {
       indexes = indexes || [];
       var index = arr.indexOf(value, fromIndex+1);
       console.log(index);
       if ( index != -1)
       {
          indexes.push(index);
          findIndexes(arr, value, index, indexes)
       }
    }
    var arr1 = [100, 200, 100, 300, 600, 200];
    var arr2 = [];
    var value = 200;
    findIndexes(arr1, value, -1, arr2);
    document.write(arr2);

Upvotes: 0

stdob--
stdob--

Reputation: 29172

Something like this:

var arr1 = [100, 200, 100, 300, 600, 200];
var arr2 = [1, 2, 3, 4, 5, 6];

var _arr1 = [];
var _arr2 = [];

for( var i = arr1.indexOf(200); i >= 0; i = arr1.indexOf(200,i+1) ) {
  _arr1.push(i);
  _arr2.push( arr2[i] );
}

console.log( _arr1, _arr2 );

Upvotes: 2

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