How to create and use an Array ?

Array are like lists, you can list and modify the array. The length of an array may vary. There are many ways to create an Array in Javascript.

let arr = new Array(); // An array has been created by 'new Array'

let arr = []; // An array has been created by [ ]

But it is not necessary to use the first method, Create an Array like this : put the string under quotes,

let colors = ['Green']; 

console.log(colors);
// Green

console.log(colors.length)
// 1

Don’t forget to verify if everything is ok, with console.log() Access (via index) an array element

// Red

Add an element at the start of your table :

let newColors = colors.unshift('Red');

// ['Red','Green'];

Add an element at the end of your array :

let newColors = colors.push('Blue');
// ['Red','Green','Blue'];

Find an element in your array by his index :

let posGreen = colors.indexOf('Green');

console.log(posGreen);
// 1

Then remove it by his index :

let removedGreen = colors.splice(posGreen, 1); 
// Delete an element from posGreen;

console.log(colors);
// ['Red', 'Blue'];

Delete the first element of your array :

let firstElement = colors.shift();
// 'Red' has been deleted

console.log(colors);
/ ['Green','Blue'];

Delete the last element of your array :

let lastElement = colors.pop(); 
// 'Blue' has been deleted

console.log(colors);
// Green

Copy an array :

let copyArray = colors.slice();

console.log(copyArray);
// Green

How to acceed to an element of an array :

let array = ['Green','Blue','Red','Black','Yellow','Brown','White'];

console.log(array[0]);// Show the first element of the array
// Green 
console.log(array[1]); // Show the second element of the array 
// Blue
console.log(array[4]); // Show the 5th element of the array
// Yellow
console.log(array[array.length - 1]); // Show the last element of the array