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104 Chapter 5: ActionScript Core Language Elements
Description
Operator; initializes a new array or multidimensional array with the specified elements (
a0
, and so
on), or accesses elements in an array. The array access operator lets you dynamically set and
retrieve instance, variable, and object names. It also lets you access object properties.
Usage 1: An array is an object whose properties are called
elements
, which are each identified by a
number called an index . When you create an array, you surround the elements with the array
access ([]) operator (or brackets ). An array can contain elements of various types. For example, the
following array, called
employee
, has three elements; the first is a number and the second two are
strings (inside quotation marks):
var employee:Array = [15, "Barbara", "Jay"];
You can nest brackets to simulate multidimensional arrays. You can nest arrays up to 256 levels
deep. The following code creates an array called
ticTacToe
with three elements; each element is
also an array with three elements:
var ticTacToe:Array = [[1, 2, 3], [4, 5, 6], [7, 8, 9]];
Usage 2: Surround the index of each element with brackets ([]) to access it directly; you can add a
new element to an array, or you can change or retrieve the value of an existing element. The first
index in an array is always 0, as shown in the following example:
var my_array:Array = new Array();
my_array[0] = 15;
my_array[1] = "Hello";
my_array[2] = true;
You can use brackets ([]) to add a fourth element, as shown in the following example:
my_array[3] = "George";
You can use brackets ([]) to access an element in a multidimensional array. The first set of brackets
identifies the element in the original array, and the second set identifies the element in the nested
array. The following line of code sends the number 6 to the log file.
var ticTacToe:Array = [[1, 2, 3], [4, 5, 6], [7, 8, 9]];
trace(ticTacToe[1][2]);// output: 6
Usage 3: You can use the array access ([]) operator instead of the
eval()
function to dynamically
set and retrieve values for movie clip names or any property of an object. The following line of
code sends the number 6 to the log file.
name["mc" + i] = "left_corner";
For more information, see “Operator precedence and associativity” on page 32 .
Example
The following example shows two ways to create a new empty Array object; the first line uses
brackets ([]):
var my_array:Array = [];
var my_array:Array = new Array();