ActionScript for Flash MX: The Definitive Guide, Second Edition

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

Named Array Elements

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(push(), pop(), etc., covered later in this chapter) and are not considered part of the

array’s numbered element list. For example, an array with one named element and

two numbered elements will have a

length of 2, not 3. To access all the named ele-

ments in an ActionScript array, therefore, we must use a for-in loop (discussed in

Chapter 8), which lists both named and numbered elements.

An array’s named elements are simply object properties. In Action-

Script, a generic object can hold a group of related properties as legiti-

mately as an array can hold named elements. Both approaches are

common practice.

Creating and Referencing Named Array Elements

To add an element that can later be retrieved by name, we use the familiar square

brackets, with a string in place of the index number, on an existing array:

arrayName[elementName] = expression

where elementName is a string. For example:

var importantDates = new Array(); // Create an empty array

importantDates["dadsBirthday"] = "June 1"; // Add a named element

importantDates["mumsBirthday"] = "January 16"; // Add another named element

Remember to create an empty array using the new Array() constructor before trying

to add named elements to it. We can also use the dot operator to specify a named

array element, as follows: ...