Javascript Array |
Array is a special kind of variable that can hold multiple values. If you recall the lesson on JS variables, we explained that variable is a container of a value.
Lets use analogy of a box. A simple variable is a box that holds one item like box containing a large chocolate cake. Now imagine array as a box that has many subdivisions and each compartment has a pastry of a different flavor.
- Box compartment 1 holds value = strawberry flavor
- Compartment 2 value= Vanilla and so on
Practically Array is many variables within one.
Why do we need Javascript Arrays / Advantages of using Arrays
- When we have to loop through many variables, it is much simpler to reference sub container id (usually called index) numbers instead of individual variable names. For example- looping through marks of students to check the highest score. Either write individual variable names OR array name 'student' and id 1 to 50. easier to loop through digits 1 to 50 than text names.
- All the data in the array is of same type like text, numerical etc. so it is easier to work with.
Syntax Define / Create Array- Method 1
First create an array, then assign values to its individual indexes.
var arrayname = new Array ();
arrayname[0] = "value";
arrayname[1] = "value";
arrayname[2] = "value";
arrayname[3] = "value"; And so on
Notice that the subcontainer IDs start from 0
Example
Notice how we referred to the 3rd index the array using the document.write command to display it on browser screen.
Syntax Create Array- Method 2
Create an array and assign value in the same statement / command
var arrayname = new Array("value", "value", "value");
Example
Both Methods are valid. Use the one you find easier and faster.
