User Guide

58 Chapter 2: ActionScript Language Reference
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 lines of code send the number 6 to the Output panel.
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 Output panel.
name["mc" + i] = "left_corner";
For more information, see “Operator precedence and associativity” in Using ActionScript in Flash.
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();
The following example creates an array called employee_array and uses the trace() statement
to send the elements to the Output panel. In the fourth line, an element in the array is changed,
and the fifth line sends the newly modified array to the Output panel:
var employee_array = ["Barbara", "George", "Mary"];
trace(employee_array); // output: Barbara,George,Mary
employee_array[2] = "Sam";
trace(employee_array); // output: Barbara,George,Sam
In the following example, the expression inside the brackets ("piece" + i) is evaluated and the
result is used as the name of the variable to be retrieved from the
my_mc movie clip. In this
example, the variable
i must live on the same Timeline as the button. If the variable i is
equal to 5, for example, the value of the variable
piece5 in the my_mc movie clip is displayed in
the Output panel:
myBtn_btn.onRelease = function() {
x = my_mc["piece"+i];
trace(x);
};