Comparing two arrays in Javascript to find identical values

Question

Comparing two arrays in Javascript to find identical values

I am faced with a challenge involving three arrays. One array contains static values, another array contains dynamic values, and the third array is intended to store values that are present in both of the other arrays.

My goal is to iterate through the arrays and identify matching values. When a match is found, that value should be added to a separate array.

This is what I am aiming for:

Array1 = ["Store1", "Store2", "Store3", "Store4"];
Array2 = ["Store6", "Store1", "Store3", "Store999"];
MatchedArray = ["Store1", "Store3"]; // should contain these values

However, I am not keen on using nested for loops like this:

  for(var arr1 = 0; arr1 < Array1.length; i++){
    for(var arr2 = 0; arr2 < Array2.length; i++){
      if(Array1[arr1].toLowerCase() == Array2[arr2].toLowerCase(){
        console.log('store found');
        duplicateArray.push(Array1[i].toLowerCase());
      }
    }
  }

I would like to explore alternative methods such as using the .map or filter function to achieve this task.

javascript arrays

Answer 1

Answer №1

To achieve the desired result, you can utilize a combination of Array#filter along with Array#includes :

const arr1 = [ 'Store1', 'Store2', 'Store3', 'Store4'];
let arr2 = [ 'Store6', 'Store1', 'Store3', 'Store999'];

let result = arr2.filter(item => arr1.includes(item));
console.log(result);

Answer 2

To achieve the desired result, you can utilize a combination of Array#filter along with Array#includes :

const arr1 = [ 'Store1', 'Store2', 'Store3', 'Store4'];
let arr2 = [ 'Store6', 'Store1', 'Store3', 'Store999'];

let result = arr2.filter(item => arr1.includes(item));
console.log(result);

Answer 3

Answer №2

Alternatively, you can create a versatile function to find the intersection of arrays

 var findArrayIntersection = function(){
    return Array.from(arguments).reduce(function(previous, current){
    return previous.filter(function(element){
      return current.indexOf(element) > -1;
   });
  });
 };

 var result = findArrayIntersection([1,2,3],[2,3,4]);  // You can also input multiple arrays
 console.log(result);

Answer 4

Alternatively, you can create a versatile function to find the intersection of arrays

 var findArrayIntersection = function(){
    return Array.from(arguments).reduce(function(previous, current){
    return previous.filter(function(element){
      return current.indexOf(element) > -1;
   });
  });
 };

 var result = findArrayIntersection([1,2,3],[2,3,4]);  // You can also input multiple arrays
 console.log(result);

Answer 5

Answer №3

Using the filter method, we can filter out items from one array and then check if the other array contains those items by utilizing Array.includes():

var Array1 = [ 'Store1', 'Store2', 'Store3', 'Store4'];
var Array2 = [ 'Store6', 'Store1', 'Store3', 'Store999'];
var MatchedArray = Array1.filter(function(s) {
  return Array2.includes(s);
});

console.log(MatchedArray);

Answer 6

Using the filter method, we can filter out items from one array and then check if the other array contains those items by utilizing Array.includes():

var Array1 = [ 'Store1', 'Store2', 'Store3', 'Store4'];
var Array2 = [ 'Store6', 'Store1', 'Store3', 'Store999'];
var MatchedArray = Array1.filter(function(s) {
  return Array2.includes(s);
});

console.log(MatchedArray);

Answer 7

Answer №4

const storesArray1 = [ "ShopA", "ShopB", "ShopC", "ShopD"];
const storesArray2 = [ "ShopF", "ShopA", "ShopC", "ShopG"];

const matchingStores = storesArray1.filter(function(store) {
return storesArray2.indexOf(store) != -1;
});

matchingStores
(2) ["ShopA", "ShopC"]

Answer 8

const storesArray1 = [ "ShopA", "ShopB", "ShopC", "ShopD"];
const storesArray2 = [ "ShopF", "ShopA", "ShopC", "ShopG"];

const matchingStores = storesArray1.filter(function(store) {
return storesArray2.indexOf(store) != -1;
});

matchingStores
(2) ["ShopA", "ShopC"]

Answer 9

Answer №5

To achieve the desired outcome, one can leverage the array.filter method.

var filtered = arr1.filter(function(val) {
    return arr2.indexOf(val) >= 0
})

The purpose of this function is to filter array elements based on a specific condition. In this case, the condition revolves around verifying the presence of 'val' in 'arr2'.

Answer 10

To achieve the desired outcome, one can leverage the array.filter method.

var filtered = arr1.filter(function(val) {
    return arr2.indexOf(val) >= 0
})

The purpose of this function is to filter array elements based on a specific condition. In this case, the condition revolves around verifying the presence of 'val' in 'arr2'.

Answer 11

Answer №6

If you're looking to find the intersection of multiple arrays, Underscore.js provides a simple solution for this task. You can check out the documentation here.

var Array1 = [ 'Store1', 'Store2', 'Store3', 'Store4'];
var Array2 = [ 'Store6', 'Store1', 'Store3', 'Store999'];
var Array3 = [ 'Store1', 'Store5', 'Store3', 'Store201'];
var common = _.intersection( Array1 ,Array2, Array3);
console.log(common);

<script src="https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.8.3/underscore-min.js"></script>

Answer 12

If you're looking to find the intersection of multiple arrays, Underscore.js provides a simple solution for this task. You can check out the documentation here.

var Array1 = [ 'Store1', 'Store2', 'Store3', 'Store4'];
var Array2 = [ 'Store6', 'Store1', 'Store3', 'Store999'];
var Array3 = [ 'Store1', 'Store5', 'Store3', 'Store201'];
var common = _.intersection( Array1 ,Array2, Array3);
console.log(common);

<script src="https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.8.3/underscore-min.js"></script>

Comparing two arrays in Javascript to find identical values

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

Answer №6

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