How to compare array 1[array of objects] with array 2 in javascript

Question

I want to compare with array 1 with array 2, array 1 has array of objects. whatever items available in array 2 those should be also available on array 1. If so, then, i have to push the item from array 2 to new array, then, i return newly created finalArray. I did the code and it is working fine as i mentioned, But, this below code executes the 'for loop' many items that i don't want.

I wanted to avoid many loop execution.

var arr1 = [{"count":1,"name":"hitler"},{"count":1,"name":"cool"},{"count":1,"name":"cooola"},{"count":1,"name":"cute"},{"count":1,"name":"nyle"},{"count":1,"name":""},{"count":1,"name":"path"},{"count":1,"name":"root"},{"count":1,"name":"sssstag"},{"count":1,"name":"ssssu tag"},{"count":1,"name":"sutag"},{"count":1,"name":"tag2"},{"count":1,"name":"arrogant"},{"count":1,"name":"test01"},{"count":1,"name":"test10"},{"count":1,"name":"uber"},{"count":1,"name":"union"},{"count":1,"name":"assettag"},{"count":1,"name":"wire"}];

function intersect_arrays(a, b) {

    var matches = [];

    for ( var i = 0; i < a.length; i++ ) {
        for ( var e = 0; e < b.length; e++ ) {
            if ( a[i].name === b[e] ) matches.push( b[e] );
        }
    }
    return matches;
}


var arr2 = ["hilter","arrogant","cool","uber"];

var finalArray = intersect_arrays(arr1, arr2);
console.log(finalArray);

Anybody help me with better way to achieve the same?

you just want to match only base of the name property or the combination of some other property. In the example there are two property but you are matching with the name property — Mukesh Agarwal
– Mukesh Agarwal, Commented Sep 30, 2016 at 5:24
I don't think you can do better than nested for loops. For every element in b, you need to look at up to every element in a. Some of the answers you've received are more readable using higher order functions, but they're performing the same number of operations, I believe. — Tom Coughlin
– Tom Coughlin, Commented Sep 30, 2016 at 5:30
Also, why are you using "hitler" in your code? Odd choice. That name is associated with genocide for many people. — Tom Coughlin
– Tom Coughlin, Commented Sep 30, 2016 at 5:32

gurvinder372 · Accepted Answer · 2016-09-30 05:21:23Z

Replace inner for-loops with

var matches = a.filter( function(item){ return b.indexOf( item.name ) > -1 } );

For example

var arr1 = [{
  "count": 1,
  "name": "hitler"
}, {
  "count": 1,
  "name": "cool"
}, {
  "count": 1,
  "name": "cooola"
}, {
  "count": 1,
  "name": "cute"
}, {
  "count": 1,
  "name": "nyle"
}, {
  "count": 1,
  "name": ""
}, {
  "count": 1,
  "name": "path"
}, {
  "count": 1,
  "name": "root"
}, {
  "count": 1,
  "name": "sssstag"
}, {
  "count": 1,
  "name": "ssssu tag"
}, {
  "count": 1,
  "name": "sutag"
}, {
  "count": 1,
  "name": "tag2"
}, {
  "count": 1,
  "name": "arrogant"
}, {
  "count": 1,
  "name": "test01"
}, {
  "count": 1,
  "name": "test10"
}, {
  "count": 1,
  "name": "uber"
}, {
  "count": 1,
  "name": "union"
}, {
  "count": 1,
  "name": "assettag"
}, {
  "count": 1,
  "name": "wire"
}];

var arr2 = ["hilter", "arrogant", "cool", "uber"];

function intersect_arrays(a, b) {
  var matches = a.filter(function(item) {
    return b.indexOf(item.name) > -1
  });
  matches = matches.map( function(item){ return item.name } );
  return matches;
}

console.log(intersect_arrays(arr1, arr2))

sandrooco · Accepted Answer · 2016-09-30 05:18:56Z

0

If you just want to merge the arrays see Array.concat(): http://www.w3schools.com/jsref/jsref_concat_array.asp

So your code would be this: var mergedArray = arr1.concat(arr2);

This will just put them together. If you want to merge on conditions I think this isn't the best solution.

answered Sep 30, 2016 at 5:18

sandrooco

8,87611 gold badges56 silver badges101 bronze badges

2 Comments

sandrooco Over a year ago

Sorry for bad formatting. Wrote this mobile, so no formatting is available. Will update.

User123 Over a year ago

You misunderstood. I dont want to merge, i want to check with array1, if it is available, then push to new array.

Suresh Gogu · Accepted Answer · 2016-09-30 05:24:11Z

0

You can Replace your two for loops with this

for ( var i = 0; i < a.length; i++ ) {
    if (b[e].indexOf(a[i].name) != -1) {
        matches.push( b[e] );
    }
}

answered Sep 30, 2016 at 5:24

Suresh Gogu

3895 silver badges12 bronze badges

Comments

synthet1c · Accepted Answer · 2016-09-30 05:35:50Z

You could use a more functional approach with Array.reduce and Array.indexOf to generate your result. This however is pretty much the same code that you have posted, but the ugly parts have been abstracted away.

const arr1 = [
  {"count":1,"name":"hitler"},{"count":1,"name":"cool"}, 
  {"count":1,"name":"cooola"},{"count":1,"name":"cute"},
  {"count":1,"name":"nyle"},{"count":1,"name":""},
  {"count":1,"name":"path"},{"count":1,"name":"root"},
  {"count":1,"name":"sssstag"},{"count":1,"name":"ssssu tag"},
  {"count":1,"name":"sutag"},{"count":1,"name":"tag2"},
  {"count":1,"name":"arrogant"},{"count":1,"name":"test01"},
  {"count":1,"name":"test10"},{"count":1,"name":"uber"},
  {"count":1,"name":"union"},{"count":1,"name":"assettag"},
  {"count":1,"name":"wire"}
];

const arr2 = ["hilter","arrogant","cool","uber"];

const intersect_arrays = function(arr, keys) {
  // reduce the array of objects
  return arr.reduce((acc, x) => {
    // check if the name property is contained in the keys array
    if (~keys.indexOf(x.name)) {
      // add the name to the returned values
      return acc.concat(x.name)
    }
    return acc
  }, [])  
}  

console.log(intersect_arrays(arr1, arr2))

Ignacio · Accepted Answer · 2016-09-30 06:23:45Z

Here's a couple of options:

OPTION1:

use indexOf to avoid the second loop.

var arr1 = [{"count":1,"name":"hitler"},{"count":1,"name":"cool"},{"count":1,"name":"cooola"},{"count":1,"name":"cute"},{"count":1,"name":"nyle"},{"count":1,"name":""},{"count":1,"name":"path"},{"count":1,"name":"root"},{"count":1,"name":"sssstag"},{"count":1,"name":"ssssu tag"},{"count":1,"name":"sutag"},{"count":1,"name":"tag2"},{"count":1,"name":"arrogant"},{"count":1,"name":"test01"},{"count":1,"name":"test10"},{"count":1,"name":"uber"},{"count":1,"name":"union"},{"count":1,"name":"assettag"},{"count":1,"name":"wire"}];

function intersect_arrays(a, b) {
var matches = [];        
a.forEach(function(item){
  if(b.indexOf(item.name) > -1) {
    matches.push(item.name);
  }
});
return matches;
}


var arr2 = ["hilter", "arrogant", "cool", "uber"];

var finalArray = intersect_arrays(arr1, arr2);

console.log(finalArray);

OPTION 2:

You could also use filter and map to do it in a more declarative way.

var arr1 = [{"count":1,"name":"hitler"},{"count":1,"name":"cool"},{"count":1,"name":"cooola"},{"count":1,"name":"cute"},{"count":1,"name":"nyle"},{"count":1,"name":""},{"count":1,"name":"path"},{"count":1,"name":"root"},{"count":1,"name":"sssstag"},{"count":1,"name":"ssssu tag"},{"count":1,"name":"sutag"},{"count":1,"name":"tag2"},{"count":1,"name":"arrogant"},{"count":1,"name":"test01"},{"count":1,"name":"test10"},{"count":1,"name":"uber"},{"count":1,"name":"union"},{"count":1,"name":"assettag"},{"count":1,"name":"wire"}];

function intersectArrays(a, b) {
return a.filter(function(item){
  return (b.indexOf(item.name) > -1)
});
}


var arr2 = ["hilter", "arrogant", "cool", "uber"];

var finalArray = intersectArrays(arr1, arr2).map(function(item) {
  return item.name;
});

console.log(finalArray);

Collectives™ on Stack Overflow

How to compare array 1[array of objects] with array 2 in javascript

5 Answers 5

Comments

2 Comments

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

5 Answers 5

Comments

2 Comments

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related