JavaScript

An Array is a special variable in JavaScript that can store multiple values in a single variable.

Instead of creating separate variables for each value:

let item1 = "Apple";
let item2 = "Banana";
let item3 = "Mango";

You can use an array:

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

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✅ How to Create an Array

1. Using Square Brackets [] (Recommended)

let cars = ["BMW", "Audi", "Mercedes"];

2. Using new Array() (Not recommended)

let bikes = new Array("Yamaha", "Suzuki", "Kawasaki");

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✅ Accessing Array Elements

Array elements are accessed using their index (starts from 0):

let colors = ["Red", "Green", "Blue"];

console.log(colors[0]); // Red
console.log(colors[1]); // Green
console.log(colors[2]); // Blue

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✅ Array Length

Use .length to get the total number of items in the array:

let items = ["Pen", "Pencil", "Eraser"];
console.log(items.length); // 3

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✅ Modifying Arrays

Change a value:

let fruits = ["Apple", "Banana", "Mango"];
fruits[1] = "Orange";
console.log(fruits); // ["Apple", "Orange", "Mango"]

Add new item:

fruits[3] = "Grapes";

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✅ Common Array Methods

Method	Description	Example
push()	Adds element to the end	arr.push("item")
pop()	Removes last element	arr.pop()
shift()	Removes first element	arr.shift()
unshift()	Adds element to the beginning	arr.unshift("item")
length	Returns the number of elements	arr.length
indexOf()	Finds index of an item	arr.indexOf("Apple")
includes()	Checks if array contains a value	arr.includes("Mango")
join()	Converts array to string	arr.join(", ")
slice()	Extracts part of the array	arr.slice(1, 3)
splice()	Add/remove elements	arr.splice(2, 0, "item")
reverse()	Reverses array order	arr.reverse()
sort()	Sorts array alphabetically (or numerically)	arr.sort()

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✅ Looping Through an Array

Using for loop:

let fruits = ["Apple", "Banana", "Mango"];
for (let i = 0; i < fruits.length; i++) {
  console.log(fruits[i]);
}

Using forEach():

fruits.forEach(function(item) {
  console.log(item);
});

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✅ Arrays Can Store Different Types

JavaScript arrays can store strings, numbers, objects, even other arrays.

let mix = ["Hello", 42, true, { name: "John" }, [1, 2, 3]];

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⚠️ Note: JavaScript Arrays are Objects

Arrays in JavaScript are technically objects, but they have special methods and behavior.

typeof ["Apple", "Banana"]; // "object"

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✅ Summary

• Arrays store multiple values in a single variable.
• Array elements are accessed by index.
• JavaScript provides many built-in methods to work with arrays.
• Arrays can store different data types.

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