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.
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