ActionScript for Flash MX: The Definitive Guide, Second Edition

This is the Title of the Book, eMatter Edition

Copyright © 2007 O’Reilly & Associates, Inc. All rights reserved.

246

Chapter 11

CHAPTER 11

Arrays

Back in Chapter 3, we saw that primitive datatypes—strings, numbers, Booleans,

null, and undefined—represent basic information in our scripts. We also saw that

ActionScript supports several composite datatypes, which can group several pieces of

data together into a single datum.

The array type is the first composite datatype we’ll study. Arrays are used to store

and manipulate ordered lists of information and are, therefore, fundamental tools in

sequential, repetitive programming. We use them to do everything from storing val-

ues retrieved via a user-input form, to generating pull-down menus, to keeping track

of enemy spacecraft in a game. In its most basic form, an array is just a list of items,

like your grocery list or the entries in your checkbook ledger.

What Is an Array?

An array is a data structure that can encompass multiple individual data values, just

like a building is a physical structure encompassing multiple floors. Unlike a primi-

tive datatype, an array can include more than one data value. Here is a simple exam-

ple showing two separate strings, followed by an array that contains two strings:

"oranges" // A single primitive string value

"apples" // Another primitive string value

["oranges", "apples"] // A single array containing two strings ...