Arrays in JavaScript

 

Arrays are ordered collections of values that can hold multiple data types (numbers, strings, objects, etc.). They are one of the most commonly used data structures in JavaScript.

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Creating Arrays

// Using array literal

let fruits = ["Apple", "Banana", "Cherry"];

// Using the Array constructor

let numbers = new Array(1, 2, 3, 4);

console.log(fruits); // ["Apple", "Banana", "Cherry"]

console.log(numbers); // [1, 2, 3, 4]

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Accessing Elements

let fruits = ["Apple", "Banana", "Cherry"];

console.log(fruits[0]); // Apple (first element)

console.log(fruits[2]); // Cherry (third element)

// Changing an element

fruits[1] = "Blueberry";

console.log(fruits); // ["Apple", "Blueberry", "Cherry"]

// Array length

console.log(fruits.length); // 3

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Common Array Methods

let fruits = ["Apple", "Banana", "Cherry"];

// push() - Add to end

fruits.push("Mango");

console.log(fruits); // ["Apple", "Banana", "Cherry", "Mango"]

// pop() - Remove from end

fruits.pop();

console.log(fruits); // ["Apple", "Banana", "Cherry"]

// shift() - Remove from start

fruits.shift();

console.log(fruits); // ["Banana", "Cherry"]

// unshift() - Add to start

fruits.unshift("Strawberry");

console.log(fruits); // ["Strawberry", "Banana", "Cherry"]

// slice() - Copy part of array

let newFruits = fruits.slice(1, 3);

console.log(newFruits); // ["Banana", "Cherry"]

// splice() - Add/Remove items at specific index

fruits.splice(1, 1, "Kiwi"); // Remove 1 element at index 1 and add "Kiwi"

console.log(fruits); // ["Strawberry", "Kiwi", "Cherry"]

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Looping Through Arrays

For Loop

let fruits = ["Apple", "Banana", "Cherry"];

for (let i = 0; i < fruits.length; i++) {

  console.log(fruits[i]);

}

for...of Loop

for (let fruit of fruits) {

  console.log(fruit);

}

forEach() Method

fruits.forEach(function(fruit, index) {

  console.log(index, fruit);

});