Flash CS3 Documentation

ActionScript 2.0 Language Reference > ActionScript classes > Array > length (Array.length property)

length (Array.length property)

A non-negative integer specifying the number of elements in the array. This property is automatically updated when new elements are added to the array. When you assign a value to an array element (for example, my_array[index] = value), if index is a number, and index+1 is greater than the length property, the length property is updated to index+1.

Note: If you assign a value to the length property that is shorter than the existing length, the array will be truncated.

Availability: ActionScript 1.0; Flash Player 5

Example

The following code explains how the length property is updated. The initial length is 0, and then updated to 1, 2, and 10. If you assign a value to the length property that is shorter than the existing length, the array will be truncated:

var my_array:Array = new Array();
trace(my_array.length); // initial length is 0
my_array[0] = "a";
trace(my_array.length); // my_array.length is updated to 1
my_array[1] = "b";
trace(my_array.length); // my_array.length is updated to 2
my_array[9] = "c";
trace(my_array.length); // my_array.length is updated to 10
trace(my_array); 
// displays: 
// a,b,undefined,undefined,undefined,undefined,undefined,undefined,undefined,c

// if the length property is now set to 5, the array will be truncated
my_array.length = 5; 
trace(my_array.length); // my_array.length is updated to 5
trace(my_array); // outputs: a,b,undefined,undefined,undefined

Flash CS3