ActionScript for Flash MX: The Definitive Guide, Second Edition

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

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Chapter 11: Arrays

As a matter of good form, you should always avoid using illegal identifiers as named

elements, despite the flexibility of the

[] operator.

Removing Named Elements

To rid an array of an unwanted named element, we use the delete operator, which we

introduced in Chapter 5:

delete arrayName.elementName

Deleting a named element destroys both the element value and the element con-

tainer, freeing up any memory being occupied by the element and its contents. (Con-

trast this with the delete operator’s behavior for numbered elements, where it simply

clears the value but leaves the container intact.)

Adding Elements to an Array

You can add elements to an array by specifying a value for a new element, increasing

the array’s

length property, or using one of the built-in array functions.

Adding New Elements Directly

We can add a new element to an existing array at a specific index simply by assign-

ing a value to that element:

// Create an array, and assign it three values

var myList = ["apples", "oranges", "pears"];

// Add a fourth value

myList[3] = "tangerines";

The new element does not need to be placed immediately after the last element of the

old array. If we place the new element more than one element beyond the end of the

array, ActionScript automatically creates undefined