What is an Array?

An array in JavaScript is a fundamental data structure that allows you to store an ordered collection of items under a single variable name. These values can be of any data type, such as numbers, strings, or even other arrays. Arrays are indexed starting from 0 in Js.

typeof array in Js is : object.

Why do we need Arrays in JavaScript?

• Storing large amount of data

• Improving performance

• Ease of use

• Better readability

• Grouping related data

• Dynamic Size

Creating Arrays:

Generally there are two ways to create a array in Js.

1.Array Literal: Using square brackets [].

// let a = [1, 2, 3, "s", "h", 6.987];
// console.log(a);

 //         try to find its output by your self
let c =[2,4]
c[10]=33
console.log(c)

2.Array Constructor: This method offers more flexibility but is generally less used.

//let a = new Array()
//console.log(a)                  //print a null array


// let b = new Array("hii",23,4.4,"gopal")
// console.log(b)


// let c= new Array(4.4)            
// console.log(c)                 // this will give error

//let d = new Array(3)    
//console.log(d)           // // Creates an array with 3 empty slots

Accessing Elements of array:

let a = [1, 2, 3,'j', "g", "s", 6.987];
console.log(a);

//                    //  to find length of array
console.log( a.length)
//console.log( a.length())   // be cautious this will give an error

console.log(a[3]) //this will print j which is 4th element as 
//index start from 0


//             //     to access all elements
for(let i =0 ;i<a.length;i++)
{
    console.log(a[i])
}

//note : try to access the element outside the size of array

Common Array Methods:

• push(): Adds one or more elements to the end of the array.

• pop(): Removes and returns the last element from the array.

• update(): we can update at any position in an array in js.

• shift(): Removes and returns the first element from the array.

• unshift(): Adds one or more elements to the beginning of the array.

• slice(): Extracts a section of the array and returns a new array.

• concat(): Merges two or more arrays and returns a new array.

• join(): Joins all elements of an array into a string, separated by a specified separator.

• reverse(): To reverse the array.

• indexof(): to find index of any element of an array.

• splice(): Used to add new items at given position:
  it has its syntax: array.splice(start, deleteCount, item1, item2, ...)

• find(): method is used to search for an element in an array that satisfies a specified condition.

Try to run following codes by yourself for better understanding.

let a = [1, 2, 3,'j', "g", "s", 6.987];
a.push(10,12);
console.log("array after pushing",a);

//                                  //pop
let a = [1, 2, 3,'j', "g", "s", 6.987];
a.pop()
console.log("array after deletion",a)

//                                 //update;
let a = [1, 2, 3,'j', "g", "s", 6.987];
a[2]= "updated"
console.log(a)

//                               //shift
let a = [1, 2, 3,'j', "g", "s", 6.987];
let r= a.shift()
console.log("array after DELETING first",r,a);
console.log("array after DELETING first : ",a);

//                              //unshift
let a = [1, 2, 3,'j', "g", "s", 6.987];
a.unshift('10')
console.log("array after pushing ",a);


//                               //slice
let a =[0,1,2,3,4,5,6,7,8]
//  console.log(a.slice(2))   // print all from index two to till last
console.log(a.slice(1,4))      // print from index 1 to n-1 i.e 3 int this case


//                                 //concat
let a =[1,2,3,4]
let b= [4,5,6,6]
let c=[6,7,8,9]
let d = a.concat(b,c)
console.log(d)


//                                 // join
  let a =[1,2,3,4]
  let e = a.join("+")
  console.log(e)

//                                  // for reverse
let r = [1,2,3,45,"hi"]
console.log(r.reverse())
//r =r.reverse()   // or 
//r.reverse
//console.log(r)

//                               // to find index
let a = [1, 2, 3,'j', "g", "s", 6.987];

console.log(a.indexOf(3))          
console.log(a.indexOf(7))            // return -1



//                 //         splice

let fruits = ["apple", "banana", "cherry", "date"];
// //Remove 1 element starting from index 2
let removed = fruits.splice(2, 1);
// fruits is now ["apple", "banana", "date"], and removed is ["cherry"]
// Remove 2 elements starting from index 1, and replace them with "kiwi" and "lemon"
fruits.splice(1, 2, "kiwi", "lemon");
// fruits is now ["apple", "kiwi", "lemon", "date"]


//          //           //   splice 

let m = [0,1,2,3,4,5,6]
// m.splice(1,0,11)

// m.splice(-14,0,111)
// console.log(m)

// m.splice(-2,0,11)
// console.log(m)

// m.splice(2,2,11)
// console.log(m)

m.splice(16,0,77)
console.log(m)

//                    //   find

let numbers = [1, 2, 3, 4, 5];

let found = numbers.find(function(element) {
  return element > 2;
});

console.log(found);

lt.32link: https://hashnode.com/post/cltkjjbk300000ala2hkm89un