Introductions to Arrays in JavaScript

 //Arrays are variables which can hold more than one value

let marks_class_12 = [91, 62, 33, 84, false, "Not Present"];

console.log(marks_class_12);

console.log(marks_class_12[0]);

console.log(marks_class_12[1]);

console.log(marks_class_12[2]);

console.log(marks_class_12[3]);

console.log(marks_class_12[4]);

console.log(marks_class_12[5]);

console.log(marks_class_12[6]); //Will be undefined because index 6 does not exist

console.log("The Length of marks_class_12 is :", marks_class_12.length);

marks_class_12[6] = 98; //Adding a new value to an Array

marks_class_12[0] = 100; // Changing the value of an Array

console.log(marks_class_12);

console.log("The Length of marks_class_12 is :", marks_class_12.length);

//In JavaScript, arrays are objects. The typeof operator on arrays returns object

console.log(typeof marks_class_12);

//Arrays can hold many values under a single name

for (let i = 0; i < marks_class_12.length; i++) {

    console.log(marks_class_12[i]);

}

OUTPUT :

[ 91, 62, 33, 84, false, 'Not Present' ] 91 62 33 84 false Not Present undefined The Length of marks_class_12 is : 6 [ 100, 62, 33, 84, false, 'Not Present', 98 ] The Length of marks_class_12 is : 7 object 100 62 33 84 false Not Present 98