JavaScript Dev

JavaScript Dev

1577716948

Add Element to Array First and Last in JavaScript

Overview

In this tutorial, you will learn how to add element or item at first or beginning and last or ending of an array in javascript.

javascript has two inbuilt functions name unshift() and push(), which is used to add elements or items at first or beginning and last or ending of an array in javascript.

This tutorial has the purpose to explain how to add element or item at first or beginning and last or ending of an array in javascript using these unshift and push functions. Also, we will explain definition, syntax, parameters, with examples.

JavaScript add Element beginning and ending of array

In this tutorial, we will show you two methods with its definition, syntax, parameters with examples to add element or item first or beginning and last or ending of an array javascript.

1. JavaScript Add Element to Array First

You can use the javascript unshift() method to add elements or items first or beginning array in javascript.

unshift() method javascript

Definition:- The javaScript unshift() method adds new items to the first or beginning of an array. and it will return the new length of array.

Syntax of unshift() method is
array.unshift(element1, element2, ..., elementX)
Parameter with description
Parameter	Description
element1, element2, …, elementX	Ii is required. The element(s) to add to the beginning of the array

Example – add element start or beginning of an array javascript

Consider, we have an array that’s the name arrNum, and it contains four elements inside it, see below:

var arrNum = [
   "one",
   "two",
   "three",
   "four"
 ];

If you want to add element start or beginning of an arrNum array. So you can use the unshift() method of javaScript like below:

var arrNum = [
   "one",
   "two",
   "three",
   "four"
 ];
 
 arrNum.unshift("zero");
 
 console.log( arrNum );
The result of the above example is:
["zero", "one", "two", "three", "four"]

2. JavaScript Add Element to Array Last

You can use the javascript push() method to add the elements or items from the last or end of an array.

push() method javascript

Definition: – The javaScript push() method is used to add a new element to the last or end of an array.

Syntax of push() method is
array.push( element1, element2, ..., elementX )
Parameter with description
Parameter	Description
element1, element2, …, elementX	Ii is required. The element(s) to add to the array

Example – javascript add the element to last or end of an array

Consider, we have an array that’s the name arrNum, and it contains four elements inside it, see below:

var arrNum = [
   "one",
   "two",
   "three",
   "four"
 ];

If you want to add the single item into the arryNum array. So you can use the push() method of javaScript like below:

var arrNum = [
   "one",
   "two",
   "three",
   "four"
 ];
 
 arrNum.push("five");
 
 console.log( arrNum );
The result of the above example is:
["one", "two", "three", "four", "five"]

#javascript #programming

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Add Element to Array First and Last in JavaScript
Lowa Alice

Lowa Alice

1624388400

JavaScript Arrays Tutorial. DO NOT MISS!!!

Learn JavaScript Arrays

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The origin of the article: https://www.youtube.com/watch?v=oigfaZ5ApsM&list=PLTjRvDozrdlxEIuOBZkMAK5uiqp8rHUax&index=4
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#arrays #javascript #javascript arrays #javascript arrays tutorial

Armando  Bruen

Armando Bruen

1590649980

How to Add Elements to an Array In Javascript

In this tutorial, you’ll be going to learn how to add elements to an array in javascript. The easiest approach to add element to array using Array.push(), Array.unshift() and Array.splice().

JavaScript array is a collection of different types of value like number, string, object and more. Which will save at a particular index, starting from 0

Add elements to an array can be done using multiple ways. If you’re a developer then it will really help you because append element to array is so crucial topic. You have to play with an array always.

There is so many interview question you will face related to this topic like how to add value at the end of an array or at the start of an array. It might be inserted value between array. So stick to the end of the post and learn everything.

#javascript #array #elements

Terry  Tremblay

Terry Tremblay

1602154740

Fill and Filter in Array in JavaScript

By the word Array methods, I mean the inbuilt array functions, which might be helpful for us in so many ways. So why not just explore and make use of them, to boost our productivity.

Let’s see them together one by one with some amazing examples.

Array.fill():

The _fill()_ method changes all elements in an array to a static value, from a start index (default _0_) to an end index (default _array.length_). It returns the modified array.

In simple words, it’s gonna fill the elements of the array with whatever sets of params, you pass in it. Mostly we pass three params, each param stands with some meaning. The first param value: what value you want to fill, second value: start range of index(inclusive), and third value: end range of index(exclusive). Imagine you are going to apply this method on some date, so that how its gonna look like eg: array.fill(‘Some date’, start date, end date).

NOTE: Start range is inclusive and end range is exclusive.

Let’s understand this in the below example-

//declare array
var testArray = [2,4,6,8,10,12,14];

console.log(testArray.fill("A"));

When you run this code, you gonna see all the elements of testArray will be replaced by 'A' like [“A”,"A","A","A","A","A","A"].

#javascript-tips #array-methods #javascript-development #javascript #arrays

6 Ways to Add Items to an Array in JavaScript

There are various ways to add or append an item to an array. We will make use of pushunshiftspliceconcatspread and index to add items to array. Let’s discuss all the 6 different methods one by one in brief.

The push() method

This method is used to add elements to the end of an array. This method returns the new array length.

const movies = ['Avengers', 'Iron-man', 'Thor'];

const newLength = movies.push('Hulk'); 

console.log(movies); // ['Avengers', 'Iron-man', 'Thor', 'Hulk'];

console.log(newLength); //4

We can also add multiple values with push method.

const movies = ['Iron-man', 'Thor']; 

movies.push('Avengers', 'Deadpool', 'Hulk');

console.log(movies); 
// ["Iron-man", "Thor", "Avengers", "Deadpool", "Hulk"]

The unshift() method

The unshift() method is used to add elements at the beginning of an array. This method returns the new array length.

const cars = ['Audi', 'BMW', 'Jaguar']; 

const newLength = cars.unshift('Mercedes'); 
console.log(newLength ); // 4 
console.log(cars); // ['Mercedes', 'Audi', 'BMW', 'Jaguar']

We can also add multiple values with unshift() method.

const cars = ['Audi', 'Jaguar']; 

cars.unshift('Mercedes', 'Tesla'); 
console.log(cars); // ['Mercedes', 'Tesla', 'Audi', 'Jaguar']

#arrays #web-development #javascript-tips #javascript #javascript-development

Cayla  Erdman

Cayla Erdman

1597470780

A quick guide to JavaScript Arrays

Introduction

Arrays are a structure common to all programming languages so knowing what they are and having a firm grasp on what you’re able to accomplish with Arrays will take you a long way in your journey as a software developer. The code examples I share in this post will be in JavaScript but the concepts are common among all languages. What you learn here can easily be translated to any other language you work with.

In this post I’ll be covering how to perform the create, read update and delete operations using arrays, some common functions that come with the Array prototype and also how to implement them.


What is an Array

Before we jump into the juicy bits of Arrays, lets quickly gloss over what they are. Arrays

  • are a fundamental data type in JavaScript
  • are an ordered collection of values called **elements **that are stored at and accessed via an index
  • are untyped, meaning that the elements of an array could be of different types. This allows us to create complex arrays such as an array of objects or even an array of arrays (multidimensional arrays)
  • can have elements that are constants or expressions
  • have a property called length that tells you the number of elements in the array
  • inherit properties from Array.prototype that includes a wide variety useful functions that can be called from arrays or array-like objects

CRUD operations using Arrays

If you’re not familiar with the term CRUD it stands for Create, Read, Update and Delete. In this section we’ll go through each one of these operations and cover different ways you can perform each one.

Creating Arrays

There are several ways you can create an Array but the most common ways are by using

  • the Array literal syntax
  • the Array constructor i.e. new Array()

Lets take a look at each one with examples

Array literal

The array literal is the most common way of creating an array. It uses the square brackets as a notion of a container followed by comma separated values inside the square brackets. The following examples show how to use the array literal syntax and how arrays are untyped i.e. can contain elements of different types.

Image for post

Examples of untyped arrays in JavaScript created with the array literal syntax.

Array constructor

Another way to create an array is through the Array constructor.

const myArray = new Array();

Using the Array constructor, as shown above, is the same as creating an array with the array literal syntax. i.e.

// The following two lines behave exactly the same way i.e. both create an empty arrays

const myArray = new Array();
const myOtherArray = [];

The array constructor, however, is able to receive arguments that allow it to behave in different ways depending on the number and type of arguments passed to it.

  • You can pass a single numeric argument which creates an array of the specified length. This option is mostly used when you know how many elements you’ll be placing in the array
const myArray = new Array(5);

Note: If you want to define the array with a specified size, as shown above, the argument passed must be a numeric value. Any other type would be considered as the first element that’ll be placed in the array.

  • Or you can pass two or more arguments or a non-numeric argument to place the values inside the array. This works the same way as shown in the array literal examples.

Image for post

Examples of arrays created by using the Array constructor in JavaScript

As stated earlier, these two ways are the most common ways of creating arrays that you’ll see and use 99% of the time. There are a few other ways but we won’t dive deep into how they work. They are

  • the spread operator const someArray = […someOtherArray]
  • the static method Array.of()
  • and the static method Array.from()

#javascript #web-development #javascript-tips #javascript-development #javascript-arrays #sql