Methods of Arrays in JavaScript

JavaScript arrays are used to store multiple values in a single variable.

Array Syntax

var array-name = [item1, item2, ...];

var colors = ["Red","Green","Black"];

Methods of Array

 

Methods of Array

1. Pop

The pop() method removes the last value of an array permanently will return the remaining values.

Example:

var mdArr = [5,6,7,8,9,5];

alert(mdArr.pop());

alert(mdArr);

Result:5 and 5,6,7,8,9

2. Push

The push() method adds the new value in the array at the end and will return the new set of array values.

Example:

var mdArr = [5,6,7,8,9,5];

alert(mdArr.push(6,8,9));

alert(mdArr);

Result:9 and 5,6,7,8,9,5,6,8,9

3. Shift

The shift() method is just like pop method. The only difference is it will remove the first value from an array permanently and return the remaining values.

Example:

var mdArr = [5,6,7,8,9,5];

alert(mdArr.shift());

alert(mdArr);

Result:5 and 6,7,8,9,5

4. Unshift

The unshift() method is the opposite of shift() method. The only difference is it will add the new values at the beginning of an array and return the new set of array values.

Example:

var mdArr = [5,6,7,8,9,5];

alert(mdArr.unshift(3,2,1));

alert(mdArr);

Result: 9 and 3,2,1,5,6,7,8,9,5

5. indexOf()

It will display the index of a given array element. If a number is appearing twice in an array, then it will return the index of first occurrence of a given number.

Example:

var mdArr = [5,6,7,8,9,5];

alert(mdArr.indexOf(5));

Result: 0

For Invalid value:

Example:

var mdArr = [5,6,7,8,9,5];

alert(mdArr.lastIndexOf(10));

Result: -1

6. lastIndexOf()

It will display the index of a given array element. If a number is appearing twice in an array, then it will return the index of last occurrence of a given number.

Example:

var mdArr = [5,6,7,8,9,5];

alert(mdArr.lastIndexOf(5));

Result: 5

For Invalid value:

Example:

var mdArr = [5,6,7,8,9,5];

alert(mdArr.lastIndexOf(10));

Result: -1

7. join()

It will join all array elements into a string specified by a separator.

Example:

var mdArr = [5,6,7,8,9,5];

alert(mdArr.join(‘’));//no space

Result: 56785

Example:

var mdArr = [5,6,7,8,9,5];

alert(mdArr.join(‘ ’));//added a space

Result: 5 6 7 8 5

Example:

var mdArr = [5,6,7,8,9,5];

alert(mdArr.join(‘*’));

Result:5*6*7*8*5

8. slice()

Syntax: slice(Begin Index, End Index)

Begin index will take the position of a given array element and will display

values depending upon the End Index value given. Last index value will not

be included.

Example:

var mdArr = [5,6,7,8,9,5];

alert(mdArr.slice(2, 4));

Result: 7,8

It will take values from 2^nd index i.e. 7 and will return values till 3^rd index. 4^th index value will not be included.

For Invalid values:

var mdArr = [5,6,7,8,9,5];

alert(mdArr.splice(8, 3));

Result: Blank Alert

9. splice()

Syntax: slice(Begin Index, No.of values)

Begin index will take the position of a given array element and will display

values depending upon the value given for No.of values given.

Example:

var mdArr = [5,6,7,8,9,5];

alert(mdArr.splice(2, 4));

Result: 7,8,9,5

It will take values from the 2^nd index i.e. 7 and will return upto 4 values.

For Invalid values:

var mdArr = [5,6,7,8,9,5];

alert(mdArr.splice(8, 3));

Result: Blank Alert