Array
let fruits = ['apple', 'banana', 'kiwi', 'grape'];
let nums = [4, 6, 204, 52, 5];
Accessing array elements:
let seasons = ['Winter', 'Spring', 'Summer', 'Autumn'];
seasons[2]; // 'Summer'
seasons[0]; // 'Winter'
List of methods and techniques which are used to modify an array itself:
Add new elements:
push
The push()
method is used to add one or more elements at the end of array.
let numbers = [4, 22, 13];
numbers.push(8); // [4, 22, 13, 8]
unshift
The unshift()
method is used to add new elements to the start of the array.
let phones = [
{ name: 'Samsung', color: 'white', number: 5 },
{ name: 'Apple', color: 'black', number: 7 },
{ name: 'Xiaomi', color: 'gold', number: 4 },
]
phones.unshift({ name: 'Huawei', color: 'blue', number: 6 });
/*
[
{ name: 'Huawei', color: 'blue', number: 6 },
{ name: 'Samsung', color: 'white', number: 5 },
{ name: 'Apple', color: 'black', number: 7 },
{ name: 'Xiaomi', color: 'gold', number: 4 },
]
*/
splice
The splice()
method is used to insert (and/or) remove elements in the array.
let animals = ['tiger', 'monkey', 'giraffe', 'fox', 'panda', 'lion'];
animals.splice(2, 0, 'elephant');
console.log(animals); // expected output: ['tiger', 'monkey', 'elephant', 'giraffe', 'fox', 'panda', 'lion']
Remove elements:
pop
The pop()
method removes the last element of the array and returns it.
let cars = ['Honda', 'Toyota', 'Nissan', 'Mercedes', 'Chevrolet', 'BMW'];
let removed = cars.pop();
console.log(cars); // expected output: ['Honda', Toyota, 'Nissan', 'Mercedes', 'Chevrolet']
console.log(removed); // expected output: 'BMW'
shift
The shift
method is used to remove first element from the array.
let colors = ['red', 'orange', 'yellow', 'pink', 'black', 'brown', 'grey'];
let removed = colors.shift();
console.log(colors); // expected output: ['orange', 'yellow', 'pink', 'black', 'brown', 'grey']
console.log(removed); // expected output: 'red'
splice
The splice()
method is used to insert (and/or) remove elements in the array.
let animals = ['tiger', 'monkey', 'giraffe', 'fox', 'panda', 'lion'];
let removed = animals.splice(2, 3, 'elephant', 'turtle');
console.log(animals); // expected output: ['tiger', 'monkey', 'elephant', 'turtle', 'lion'];
console.log(removed); //expected output: ['giraffe', 'fox', 'panda']
delete operator
let fruits = ['apple', 'kiwi', 'banana', 'peach'];
delete fruits[1];
console.log(fruits); // expected output: ['apple', undefined, 'banana', 'peach']
length
let nums = [5, 2, 72, 19, 15, 0, 23];
nums.length = 3;
console.log(nums); //expected output: [5, 2, 72]
length
:
Get the array let cars = ['Honda', 'Toyota', 'Nissan', 'Mercedes', 'Chevrolet', 'BMW'];
cars.length; // 6
slice() method or spread syntax:
Copy an array uselet actors = ['Al Pacino', 'Johnny Depp', 'Tom Hanks', 'Leonardo DiCaprio'];
let actorsCopy = actors.slice();
let actorsCopy2 = [...actors];
concat() method:
Merge two or more arrays uselet portion1 = [1, 2, 3, 4];
let portion2 = [5, 6, 7];
let nums = portion1.concat(portion2);
console.log(nums); // expected output: [1, 2, 3, 4, 5, 6, 7]