Arrays Using JavaScript

Hello Folks, In this article we are going to learn about Arrays using JavaScript.

What is an Array?

Array is a Data Structure where you can store values in a singe variable name and can access the values by referring to an index number.

var names = ['guru','hemanth','sushan'];

Accessing Array Element

You can Access any element in an Array by its index number.

var names = ['guru','hemanth','sushan'];

/ In array index number starts from 0. So the index value of guru is 0, hemanth is 1, and sushan is2/

console.log(names[1]);

/This will return an output hemanth/

Changing an Element

You change an element in an array by using its index number.

var names = ['guru','hemanth','sushan'];

names[0] = 'gaurav';

/The updated array will be/

names = ['gaurav','hemanth','sushan']

Length Property

By Using the Length property in an Array we can determine the length of the Array.

var names = ['guru','hemanth','sushan'];

console.log(names.length);

/The output will be 3 /

Adding an Element

By using an push keyword in an array we can add an element into an array. The push method adds an element to the end of the array.

var names = ['guru','hemanth','sushan'];

names.push('gaurav');

console.log(names);

/The output will be ['guru','hemanth','sushan','gaurav'] /

Removing(pop) an Element

Removing or Poping is a method in the array where you can remove or pop an element from an array.

var names = ['guru','hemanth','sushan','gaurav'];

names.pop('gaurav');

console.log(names);

/The output will be ['guru','hemanth','sushan'] /

Concatenation

By using concat we can merge two arrays.

var names = ['guru','hemanth','sushan'];

var ages = [22,32,42];

var concates = names.concat(ages);

console.log(concates);

/The output will be [ 'guru', 'hemanth', 'sushan', 22, 32, 42 ] /

Array Shift

The shift keyword removes the first element in an array and shifts all the other elements in an array to a lower index.

var names = ['guru','hemanth','sushan'];

names.shift();

console.log(names);

/ The output will be [ 'hemanth', 'sushan' ] /

Array Unshift

The unshift keyword adds the element at first in an array and unshifts the older elements.

var names = ['guru','hemanth','sushan'];
names.unshift('gaurav');

console.log(names);

/The output will be  [ 'gaurav', 'guru', 'hemanth', 'sushan' ] /

Array Splicing

Using the Splice method in an array we can add or remove an element from an array.

var names = ['guru','hemanth','sushan'];
console.log(names);

names.splice(1,2,'gaurav','wodeyar');

console.log(names);

/ Here in splice 1 is the index where elements should be added and 2 is the value where how many elements should be removed /

output:

[ 'guru', 'hemanth', 'sushan' ]
[ 'guru', 'gaurav', 'wodeyar' ]

Array Slice

The Slice method slices out a piece of an array into a new array.

var names = ['guru','hemanth','sushan','gaurav','wodeyar'];
console.log(names);

var slicedNames = names.slice(2);
console.log(slicedNames);

/ Here I have to given slice 2 so that there will be a new array  from that index /

output

[ 'guru', 'hemanth', 'sushan', 'gaurav', 'wodeyar' ]
[ 'sushan', 'gaurav', 'wodeyar' ]

Array Sort

Using the Sort method we can sort the elements in alphabetical order.

var names = ['guru','hemanth','sushan','gaurav','wodeyar'];
console.log(names);

names.sort();

console.log(names);

output

[ 'guru', 'hemanth', 'sushan', 'gaurav', 'wodeyar' ]
[ 'gaurav', 'guru', 'hemanth', 'sushan', 'wodeyar' ]

Array Reverse

Using the Array Reverse method we can reverse the array.

var names = ['guru','hemanth','sushan','gaurav','wodeyar'];
console.log(names);

names.reverse();

console.log(names);

output

[ 'guru', 'hemanth', 'sushan', 'gaurav', 'wodeyar' ]
[ 'wodeyar', 'gaurav', 'sushan', 'hemanth', 'guru' ]