Array methods in javascript.
T Shiva Kumar
Posted on August 13, 2024
There are some methods in array
1.push()
2.unshift()
3.pop()
4.shift()
5.splice()
6.slice()
7.indexOf()
8.includes()
9.forEach()
10.map()
11.filter()
12.find()
13.some()
14.every()
15.concat()
16.join()
17.sort()
18.reduce()
1 Push() method
*Add new element at last position.
syntax
array.push(element1, element2, ..., elementN)
Example
let fruits = ['apple', 'banana'];
let newLength = fruits.push('orange', 'mango');
console.log(fruits); // Output: ['apple', 'banana', 'orange', 'mango']
console.log(newLength); // Output: 4
2 unshift() method
*Add new element at initial position.
syntax
array.unshift(item1, item2, ..., itemN)
Example
const fruits = ["Banana", "Orange", "Apple"];
fruits.unshift("Lemon");
console.log(fruits); // Output: ["Lemon", "Banana", "Orange", "Apple"]
3 pop() method
*It will remove your last element.
*It will return the removed element from the array
*"undifined" if the array is empty
syntax
array.pop();
Example
const fruits = ['Apple', 'Banana', 'Cherry'];
const lastFruit = fruits.pop();
console.log(fruits); // Output: ['Apple', 'Banana']
console.log(lastFruit); // Output: 'Cherry'
4 shift() method
*It will remove your first element.
*It will return the removed element from the array
syntax
array.shift();
Example
const fruits = ['Apple', 'Banana', 'Cherry'];
const firstFruit = fruits.shift();
console.log(fruits); // Output: ['Banana', 'Cherry']
console.log(firstFruit); // Output: 'Apple'
5 splice() method
*Adds or remove elements from an array.
*splice() will modified original array.
syntax
array.splice(start, deleteCount, item1, item2, ...);
Example
let colors = ['Red', 'Green', 'Blue'];
colors.splice(1, 0, 'Yellow', 'Pink'); // Adds 'Yellow' and 'Pink' at index 1
console.log(colors); // Output: ['Red', 'Yellow', 'Pink', 'Green', 'Blue']
6 slice() method
*It is used to extract(give) the part of array.
*slice will return array.
*slice will not modified the original array.
syntax
array.slice(start, end);
Example
let numbers = [2, 3, 5, 7, 11, 13, 17];
let newArray = numbers.slice(3, 6);
console.log(newArray); // Output: [7, 11, 13]
7 indexOf() method
*The indexOf() method in JavaScript is used to find the first index at which a given element can be found in the array, or -1 if the element is not present.
syntax
array.indexOf(searchElement, fromIndex);
Example
let fruits = ['Apple', 'Banana', 'Orange', 'Banana'];
let index = fruits.indexOf('Banana');
console.log(index); // Output: 1
8 includes() method
*It is used to identify certain element is present in our array or not.
*If element is present it will return "true" otherwise return "false".
*It will return boolean value.
syntax
array.includes(searchElement, fromIndex);
Example
let numbers = [1, 2, 3, 4, 5];
let hasThree = numbers.includes(3, 2);
console.log(hasThree); // Output: true
9 forEach() method
- Executes the function for each element.
- Does not create a new array.
- Original array remains unchanged.
Example
let numbers = [1, 2, 3];
numbers.forEach((value, index, arr) => {
arr[index] = value * 2;
});
console.log(numbers); // Output: [2, 4, 6]
10 map() method
- It takes each element of an array.
- The output of map array is always array only.
- It will not change original array
- Creates a new array.
Example
const numbers = [10, 20, 30];
const incremented = numbers.map((num, index) => num + index);
console.log(incremented); // Output: [10, 21, 32]
11 filter() method
- It is used to filter elements or data from the array based on certain condition.
- If it return 'true' what ever data is store in this parameter that data will return.
- If it return 'false' then it will not return any value it returns empty array
- Creates a new array.
- Original array remains unchanged.
Example
const numbers = [1, 2, 3, 4, 5, 6];
const evenNumbers = numbers.filter(num => num % 2 === 0);
console.log(evenNumbers); // Output: [2, 4, 6]
12 find() method
- It returns the first element of array for which call back function return true.
- It return 'undifined' if the element is false or not satisfies.
- Original array remains unchanged.
Example
const numbers = [1, 3, 4, 9, 8];
function isEven(element) {
return element % 2 === 0;
}
const firstEven = numbers.find(isEven);
console.log(firstEven); // Output: 4
13 some() method
- Returns true if at least one element passes the test.
- Returns false if no elements pass the test.
- Stops testing once the first passing element is found. *Original array remains unchanged.
Example
const numbers = [2, 4, 6, 8, 10];
const hasGreaterThanFive = numbers.some(num => num > 5);
console.log(hasGreaterThanFive); // Output: true
14 every() method
- It test all the elements in the array if all the condition satisfy then it return true.
- If one condition is not satisfy then it return false.
- Original array remains unchanged.
Example
const numbers = [10, 20, 30, 40, 50];
const allGreaterThanFive = numbers.every(num => num > 5);
console.log(allGreaterThanFive); // Output: true
15 concat() method
*Combine two or more arrays and returns a new array.
Example
const fruits = ['Apple', 'Banana'];
const vegetables = ['Carrot', 'Peas'];
const grains = ['Rice', 'Wheat'];
const food = fruits.concat(vegetables, grains);
console.log(food); // Output: ['Apple', 'Banana', 'Carrot', 'Peas', 'Rice', 'Wheat']
16 join() method
*Create a new string by concatenating all the elements of an array and
return a string by a specified separator.
Example
const letters = ['J', 'o', 'i', 'n'];
const result = letters.join('');
console.log(result); // Output: 'Join'
17 sort() method
*It is used to arrange the element of an array in place and return the sorted array.
- By default the sort method sorts the element as strings in ascending order.
Example1
const numbers = [4, 2, 5, 1, 3];
numbers.sort((a, b) => a - b);
console.log(numbers); // Output: [1, 2, 3, 4, 5]
Example2
const numbers = [4, 2, 5, 1, 3];
numbers.sort((a, b) => b - a);
console.log(numbers); // Output: [5, 4, 3, 2, 1]
18 reduce() method
- perform some operations and reduce the array to a single value.
Example
let number = [1, 2, 3, 4, 5];
let sum = number.reduce((accumulator, currentValue) => {
return accumulator + currentValue;
}, 0);
console.log(sum);
Posted on August 13, 2024
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