Javascript get element from array by index

Javascript: Get element of array by index

While working in javascript, often there is a requirement to delete an element from an array by index. This article will discuss accessing an element from the javascript array by an index value.

Get an array element by index using [ ]

Get the value of element at 3 rd index position in array [1,4,9,16,25]

let numArray = [1,4,9,16,25]; var value = numArray[3]; console.log(value);

Frequently Asked:

Note that the arrays have zero-based index .

Get the value of element at 2 nd index position in array [“Javascript”, “Is”, “Popular”, “Language”]

let stringArray = ["Javascript", "Is", "Popular","Language"]; var value = stringArray[2]; console.log(value);

I hope this article helped you to get an element from an array by index position in javascript. Good Luck .

Related posts:

Share your love

Leave a Comment Cancel Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Terms of Use

Disclaimer

Copyright © 2023 thisPointer

To provide the best experiences, we and our partners use technologies like cookies to store and/or access device information. Consenting to these technologies will allow us and our partners to process personal data such as browsing behavior or unique IDs on this site and show (non-) personalized ads. Not consenting or withdrawing consent, may adversely affect certain features and functions.

Click below to consent to the above or make granular choices. Your choices will be applied to this site only. You can change your settings at any time, including withdrawing your consent, by using the toggles on the Cookie Policy, or by clicking on the manage consent button at the bottom of the screen.

The technical storage or access is strictly necessary for the legitimate purpose of enabling the use of a specific service explicitly requested by the subscriber or user, or for the sole purpose of carrying out the transmission of a communication over an electronic communications network.

The technical storage or access is necessary for the legitimate purpose of storing preferences that are not requested by the subscriber or user.

The technical storage or access that is used exclusively for statistical purposes. The technical storage or access that is used exclusively for anonymous statistical purposes. Without a subpoena, voluntary compliance on the part of your Internet Service Provider, or additional records from a third party, information stored or retrieved for this purpose alone cannot usually be used to identify you.

The technical storage or access is required to create user profiles to send advertising, or to track the user on a website or across several websites for similar marketing purposes.

Источник

Array.prototype.find()

The find() method returns the first element in the provided array that satisfies the provided testing function. If no values satisfy the testing function, undefined is returned.

• If you need the index of the found element in the array, use findIndex() .
• If you need to find the index of a value, use indexOf() . (It’s similar to findIndex() , but checks each element for equality with the value instead of using a testing function.)
• If you need to find if a value exists in an array, use includes() . Again, it checks each element for equality with the value instead of using a testing function.
• If you need to find if any element satisfies the provided testing function, use some() .

Try it

Syntax

find(callbackFn) find(callbackFn, thisArg) 

Parameters

A function to execute for each element in the array. It should return a truthy value to indicate a matching element has been found, and a falsy value otherwise. The function is called with the following arguments:

The current element being processed in the array.

The index of the current element being processed in the array.

The array find() was called upon.

A value to use as this when executing callbackFn . See iterative methods.

Return value

The first element in the array that satisfies the provided testing function. Otherwise, undefined is returned.

Description

The find() method is an iterative method. It calls a provided callbackFn function once for each element in an array in ascending-index order, until callbackFn returns a truthy value. find() then returns that element and stops iterating through the array. If callbackFn never returns a truthy value, find() returns undefined .

callbackFn is invoked for every index of the array, not just those with assigned values. Empty slots in sparse arrays behave the same as undefined .

find() does not mutate the array on which it is called, but the function provided as callbackFn can. Note, however, that the length of the array is saved before the first invocation of callbackFn . Therefore:

• callbackFn will not visit any elements added beyond the array’s initial length when the call to find() began.
• Changes to already-visited indexes do not cause callbackFn to be invoked on them again.
• If an existing, yet-unvisited element of the array is changed by callbackFn , its value passed to the callbackFn will be the value at the time that element gets visited. Deleted elements are visited as if they were undefined .

Warning: Concurrent modifications of the kind described above frequently lead to hard-to-understand code and are generally to be avoided (except in special cases).

The find() method is generic. It only expects the this value to have a length property and integer-keyed properties.

Examples

Find an object in an array by one of its properties

const inventory = [  name: "apples", quantity: 2 >,  name: "bananas", quantity: 0 >,  name: "cherries", quantity: 5 >, ]; function isCherries(fruit)  return fruit.name === "cherries"; > console.log(inventory.find(isCherries)); // 

Using arrow function and destructuring

const inventory = [  name: "apples", quantity: 2 >,  name: "bananas", quantity: 0 >,  name: "cherries", quantity: 5 >, ]; const result = inventory.find(( name >) => name === "cherries"); console.log(result); // 

Find a prime number in an array

The following example finds an element in the array that is a prime number (or returns undefined if there is no prime number):

function isPrime(element, index, array)  let start = 2; while (start  Math.sqrt(element))  if (element % start++  1)  return false; > > return element > 1; > console.log([4, 6, 8, 12].find(isPrime)); // undefined, not found console.log([4, 5, 8, 12].find(isPrime)); // 5 

Using find() on sparse arrays

Empty slots in sparse arrays are visited, and are treated the same as undefined .

// Declare array with no elements at indexes 2, 3, and 4 const array = [0, 1, , , , 5, 6]; // Shows all indexes, not just those with assigned values array.find((value, index) =>  console.log("Visited index", index, "with value", value); >); // Visited index 0 with value 0 // Visited index 1 with value 1 // Visited index 2 with value undefined // Visited index 3 with value undefined // Visited index 4 with value undefined // Visited index 5 with value 5 // Visited index 6 with value 6 // Shows all indexes, including deleted array.find((value, index) =>  // Delete element 5 on first iteration if (index === 0)  console.log("Deleting array[5] with value", array[5]); delete array[5]; > // Element 5 is still visited even though deleted console.log("Visited index", index, "with value", value); >); // Deleting array[5] with value 5 // Visited index 0 with value 0 // Visited index 1 with value 1 // Visited index 2 with value undefined // Visited index 3 with value undefined // Visited index 4 with value undefined // Visited index 5 with value undefined // Visited index 6 with value 6 

Calling find() on non-array objects

The find() method reads the length property of this and then accesses each property whose key is a nonnegative integer less than length .

const arrayLike =  length: 3, "-1": 0.1, // ignored by find() since -1 < 00: 2, 1: 7.3, 2: 4, >; console.log(Array.prototype.find.call(arrayLike, (x) => !Number.isInteger(x))); // 7.3 

Specifications

Browser compatibility

BCD tables only load in the browser

See also

• Polyfill of Array.prototype.find in core-js
• Indexed collections
• Array
• Array.prototype.findIndex()
• Array.prototype.findLast()
• Array.prototype.findLastIndex()
• Array.prototype.includes()
• Array.prototype.filter()
• Array.prototype.every()
• Array.prototype.some()
• TypedArray.prototype.find()

Found a content problem with this page?

This page was last modified on Jun 27, 2023 by MDN contributors.

Your blueprint for a better internet.

MDN

Support

Our communities

Developers

Visit Mozilla Corporation’s not-for-profit parent, the Mozilla Foundation.
Portions of this content are ©1998– 2023 by individual mozilla.org contributors. Content available under a Creative Commons license.

Источник