public length : Number

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.

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