Defining a Number Variable

Defining a Number Variable

Flash CS4 ActionScript 3.0 Tutorial


How to Assign Variable Names and Define the Number Data Type with Flash ActionScript



Variables are similar to the variables we used in math class. They store a value and over time the variable can be assigned several different values. The value assigned to a variable can change based on the script and events on the stage. For more information about number variables, see topic, Interpreting a String as a Number.

Naming a Variable

When naming variables, try to observe these rules:

No spaces

Use numbers and letters

Avoid using any special characters

Character exceptions are ($, _)

Don't use any reserved words (they appear in blue)

Never start a variable with a number

Assign a name that makes sense

Camel Case

A common practice when naming variables and instances is to use camel case. Camel case variables start with small letters. Each new word starts with a cap. There are no spaces.

Blue Cylinder converted to camel case becomes blueCylinder.


If a variable stores a value, it is generally a Number (all numbers), int (integer), or uint (positive integer). The following are examples of each:

Number: 1.325, 5.6, 410

int (integer): 3, 5, 12, -10, -30

uint (positive integer): 3, 7, 13


Step One

Option double-click (PC - Alt double-click) the first keyframe of a new blank document to open the ActionScript panel.

Step Two

Add the following code to establish a number variable named averageScore with a starting value of 21.25.

var averageScore:Number = 21.25;


Step Three

This code creates a integer variable named rouletteChips with an initial value of 0.

var rouletteChips:int = 0;


Step Four

If you wanted to create a variable called totalVisitors that would only allow positive whole values and is assigned the initial value of 1, you could use the following code.

var totalVisitors:uint = 1;


Why the trace() Statement?

In each of these examples we also included the trace statement. The trace statement allows you to see the variable value in the Flash Output panel whenever you run the script.

Trace statements are helpful in troubleshooting because you can view a variable's value at a particular point in the script.