Table of Contents
Method 1: Use filter() and includes() methods
grammar
Example
Method 2
Method 3: Using Set
Home Web Front-end JS Tutorial How to create an array from the intersection of two arrays in JavaScript?

How to create an array from the intersection of two arrays in JavaScript?

Sep 11, 2023 pm 05:05 PM

如何在 JavaScript 中使用两个数组的交集创建数组?

Intersection of two arrays in JavaScript can be done in different ways, such as using Set, spread operator, filter() method or includes() method. Each method has its own advantages and disadvantages, and it is important to consider which method is best for a given task. The intersection of two arrays can be helpful if you want to create a new array containing only the elements found in both arrays.

Let us give an example -

arr1 = [ 2, 5, 7, 9, 11, 13, 15, 17 ]
arr2 = [ 1, 3, 5, 7, 11, 13, 16, 17 ]

intersecArr = [ 5, 6, 11, 13, 17 ]
Copy after login

Above we defined two arrays arr1 and arr2, including some of the same values ​​​​that exist in the two arrays. The intersection of the two arrays is antersecArr.

Let’s discuss ways to create an array from the intersection of two arrays in JavaScript.

Method 1: Use filter() and includes() methods

We can use the filter() and includes() methods to perform intersection on two arrays. The filter() method accepts a function as its argument and applies it to each element in the array. The function should return a Boolean value of true or false indicating whether the element should be included in the new array. In our case, we want the element to be present in both input arrays, so we will use the includes() method to check if the element is present in the other array.

grammar

The following is the syntax for using the filter() and include() methods to create a new array from the intersection of two arrays -

let intersection = arr1.filter(x => arr2.includes(x));
Copy after login

The filter() method accepts a callback function as its parameter. This callback function is applied to each element of the first array (arr1) and uses the includes() method to check if the current element (x) is present in the second array (arr2). If the current element (x) exists in the second array (arr2), it is included in the new array (intersection).

If the current element (x) does not exist in the second array (arr2), exclude it from the new array (intersection). The end result is a new array (the intersection) containing only the elements present in arr1 and arr2.

Example

In the following example, we create two arrays arr1 and arr2, each with five elements, three of which are the same. Then use the filter and contain methods to create a new array of common elements from both arrays.

<html>
<head>
   <title>Creating an Array using Intersection of two Arrays using Filter() and Includes() methods</title>
</head>
<body>
   <p id="arr1"></p>
   <p id="arr2"></p>
   <p id="result"></p>
   <script>
      let arr1 = [5, 6, 8, 11, 15];
      let arr2 = [3, 5, 8, 11, 17];
            
      document.getElementById("arr1").innerHTML = "Array 1: " + JSON.stringify(arr1);
      document.getElementById("arr2").innerHTML = "Array 1: " + JSON.stringify(arr2);
            
      const intersection = arr1.filter(x => arr2.includes(x));

      document.getElementById("result").innerHTML = "Intersection of Array1 & Array 2: " + JSON.stringify(intersection);
   </script>
</body>
</html>
Copy after login

The above code will create a new array, intersectionArray, which only contains elements that are present in both input arrays.

Method 2

In this method, we first create a new collection object from the elements of arr1. It removes any duplicate elements. Then use the spread operator to convert the collection object to an array. The array has no duplicate elements. Now we use filter() and include() methods to perform intersection. The further process is the same as the first method.

let intersection = [...new Set(arr1)].filter(x => arr2.includes(x));
Copy after login

The above syntax creates a new array "intersection". After removing all duplicates from arr1, it contains elements present in arr1 and arr2.

Example



   Creating an Array using Intersection of two Arrays using Spread Operator and Filter() method


   

<script> let arr1 = [4, 8, 12, 16, 20, 28]; let arr2 = [8, 16, 20, 24, 28, 30]; document.getElementById("arr1").innerHTML = "Array 1: " + JSON.stringify(arr1); document.getElementById("arr2").innerHTML = "Array 1: " + JSON.stringify(arr2); let intersection = [...new Set(arr1)].filter(x =&gt; arr2.includes(x)); document.getElementById("result").innerHTML = "Intersection of Array1 & Array 2: " + JSON.stringify(intersection); </script>
Copy after login

Method 3: Using Set

In this method, first, we use the new Set() constructor to convert the array into a set. Then use a for...of loop to iterate over the elements of the second set. Then use the has() method to check if the element is in the first Set. If the element exists in the first Set, use the push() method to add the element to the intersection array.

Example

<html>
<head>
   <title>Creating an Array using Intersection of two Arrays using Set</title>
</head>
<body>
   <p id="arr1"></p>
   <p id="arr2"></p>
   <p id="result"></p>
   <script>
      function doIntersection(arr1, arr2) {
         const setFirst = new Set(arr1);
         const setSecond = new Set(arr2);
         let intersection = [];
         for (let i of setSecond) {
            if (setFirst.has(i)) {
               intersection.push(i);
            }
         }
         return intersection;
      }

      const arrFirst = [4, 6, 8, 10, 12];
      const arrSecond = [4, 5, 8, 12, 15];

      document.getElementById("arr1").innerHTML = "Array 1: " + JSON.stringify(arrFirst);
      document.getElementById("arr2").innerHTML = "Array 1: " + JSON.stringify(arrSecond);

      const interResult = doIntersection(arrFirst, arrSecond);

      document.getElementById("result").innerHTML = "Intersection of Array1 & Array 2: " + JSON.stringify(interResult);
   </script>
</body>
</html>
Copy after login

In this tutorial, we have discussed three ways to create an array using the intersection of two arrays with the help of examples. In the first method, we use filter() and include() methods, while in the second method, in addition to filter and include, we also use spread operator and Set. In the third approach, we create a custom function to perform this task.

The above is the detailed content of How to create an array from the intersection of two arrays in JavaScript?. For more information, please follow other related articles on the PHP Chinese website!

Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

What should I do if I encounter garbled code printing for front-end thermal paper receipts? What should I do if I encounter garbled code printing for front-end thermal paper receipts? Apr 04, 2025 pm 02:42 PM

Frequently Asked Questions and Solutions for Front-end Thermal Paper Ticket Printing In Front-end Development, Ticket Printing is a common requirement. However, many developers are implementing...

Who gets paid more Python or JavaScript? Who gets paid more Python or JavaScript? Apr 04, 2025 am 12:09 AM

There is no absolute salary for Python and JavaScript developers, depending on skills and industry needs. 1. Python may be paid more in data science and machine learning. 2. JavaScript has great demand in front-end and full-stack development, and its salary is also considerable. 3. Influencing factors include experience, geographical location, company size and specific skills.

Demystifying JavaScript: What It Does and Why It Matters Demystifying JavaScript: What It Does and Why It Matters Apr 09, 2025 am 12:07 AM

JavaScript is the cornerstone of modern web development, and its main functions include event-driven programming, dynamic content generation and asynchronous programming. 1) Event-driven programming allows web pages to change dynamically according to user operations. 2) Dynamic content generation allows page content to be adjusted according to conditions. 3) Asynchronous programming ensures that the user interface is not blocked. JavaScript is widely used in web interaction, single-page application and server-side development, greatly improving the flexibility of user experience and cross-platform development.

How to merge array elements with the same ID into one object using JavaScript? How to merge array elements with the same ID into one object using JavaScript? Apr 04, 2025 pm 05:09 PM

How to merge array elements with the same ID into one object in JavaScript? When processing data, we often encounter the need to have the same ID...

How to achieve parallax scrolling and element animation effects, like Shiseido's official website?
or:
How can we achieve the animation effect accompanied by page scrolling like Shiseido's official website? How to achieve parallax scrolling and element animation effects, like Shiseido's official website? or: How can we achieve the animation effect accompanied by page scrolling like Shiseido's official website? Apr 04, 2025 pm 05:36 PM

Discussion on the realization of parallax scrolling and element animation effects in this article will explore how to achieve similar to Shiseido official website (https://www.shiseido.co.jp/sb/wonderland/)...

The difference in console.log output result: Why are the two calls different? The difference in console.log output result: Why are the two calls different? Apr 04, 2025 pm 05:12 PM

In-depth discussion of the root causes of the difference in console.log output. This article will analyze the differences in the output results of console.log function in a piece of code and explain the reasons behind it. �...

Is JavaScript hard to learn? Is JavaScript hard to learn? Apr 03, 2025 am 12:20 AM

Learning JavaScript is not difficult, but it is challenging. 1) Understand basic concepts such as variables, data types, functions, etc. 2) Master asynchronous programming and implement it through event loops. 3) Use DOM operations and Promise to handle asynchronous requests. 4) Avoid common mistakes and use debugging techniques. 5) Optimize performance and follow best practices.

How to implement panel drag and drop adjustment function similar to VSCode in front-end development? How to implement panel drag and drop adjustment function similar to VSCode in front-end development? Apr 04, 2025 pm 02:06 PM

Explore the implementation of panel drag and drop adjustment function similar to VSCode in the front-end. In front-end development, how to implement VSCode similar to VSCode...

See all articles