Array Method
Published: 2023-03-19 09:40:21

Array is a collection of similar data elements stored at contiguous memory locations. It is the simplest data structure where each data element can be accessed directly by only using its index number. 
In array index number start with 0.
Array data  [hello, array, java, c++, 1, 56, 23]
Array index [ 0   ,   1  ,   2 ,  3 , 4, 5  ,6 ]

## Array Method
**Array Length**
array length use for get total number of array. How many elements stored in array

```
let name = ['hello', 'world', 'Asia', 'india', 'america']
console.log(name.length)

outpur: 5
```
_Total number of element is 5_

**Push** 
Insert the new value inside array but value/element will stored in last.

```
let namess = [12, 45, 76, 24, 46]
namess.push('VYOM','rah');
console.log(namess);

output: [12, 45, 76, 24, 46, 'VYOM','rah']
```
**Slice**
The `slice()` method returns a shallow copy of a portion of an array into a new array object selected from start to end ( end not included) where start and end represent the index of items in that array.
_Syntax_
slice()
slice(start)
slice(start, end)

```
let namess = [12, 45, 76, 24, 46, 23, 86, 96]
console.log(namess.slice(1,7);

output: [ 45, 76, 24, 46, 23, 86 ]
```

**Splice**
The `splice()` method changes the contents of an array by removing or replacing existing elements and/or adding new elements
_Syntax_
splice(start)
splice(start, deleteCount)
splice(start, deleteCount, item1)
splice(start, deleteCount, item1, item2, itemN)

```
let fruit = ['1', '2', '3', '4', 5, 6, 7, 8];
fruit.splice(2, 1, 'Apple', 'Banana');
console.log(fruit);

output: [ '1', '2', 'Apple', 'Banana', '4', 5, 6, 7, 8 ]
```
**Concatenation**
The `Concatenation`method add two array.

```
let arr1 = [1, 2, 3, 4];
let arr2 = [5, 6, 7];
let arr3 = [8, 9, 10, 11, 12]; 
console.log(arr1.concat(arr2, arr3));

output: [1, 2, 3, 4, 5 , 6, 7, 8, 9, 10, 11, 12]
```

**Include**
The `include` method returns "true or false" if the value stored in correct index output will "true" else output will be false.

```
let num = [1, 2, 3, 4, 5, 6, 7, 8];
console.log(num.includes(7, 6));

output: True

let num = [1, 2, 3, 4, 5, 6, 7, 8];
console.log(num.includes(7, 8));

output: false
```
_7 is a value and 6 is index no. so 7 is stored in index of 6 output is true 
if (7,8) it's mean 7 is stored index of 8 which is false because 7 is stored in index of 6_

**Indexof**
`Indexof` method use to get index number of value means in which index no. value is stored.

```
let num = [1, 2, 3, 'Anurag', 4, 5, 6, 7, 8];
console.log(num.indexOf('Anurag'));

output: 3
```
if the same value stored multiple times in same array in that case output will only one index number which come first.

**Is Array**
`isarray` Method use is this array or not if it is than output will true is not output will false 

```
let num = [1, 2, 3, 'Anurag', 4, 5, 6, 7, 8, 'Anurag', 'Anurag'];
console.log(Array.isArray(num));

output: True

let num1= dreamworld
console.log(Array.isArray(num1));

output: false
```

**Join**
The `join` method use when we want to add a value in array with all the value of array.

```
let Arr1 = [1, 2, 3, 4, 5, 6, 7];
let var1 = Arr1.join(' a '); //a will join all value of array
console.log(var1);

output:1 a 2 a 3 a 4 a 5 a 6 a 7 

```
lots Array method are available.