ActionScript: The Definitive Guide

Name

Array.length Property — the number of elements in an array

Availability

Flash 5

Synopsis

array.length

Access

Read/write

Description

The length property is a non-negative integer specifying the number of elements in an array. An array with no elements has a length of 0, an array with 2 elements has a length of 2. Note that the index number of the first element in an array is 0, so length is always one greater than the index of the last element in the array.

The length property of an array indicates how many numbered elements the array currently contains, including empty elements (those containing null or undefined). For example, an array may have values for elements 0, 1, 2, and 9, but elements 3 through 8 may be empty. Such an array has a length of 10 because it has 10 element positions (0 through 9) even though only 4 positions are occupied by useful values.

Setting the length of an array changes the number of elements in the array. If we increase length, empty elements are added to the end of the array; if we decrease length, existing elements are removed from the end of the array. The length property changes automatically whenever any elements are added or removed via the Array class methods. The length property reflects numbered elements only; it does not include named array elements, which are treated as properties of the array.

Example

myList = new Array("one", "two", "three"); trace(myList.length); // Displays: 3 // Loop through the array's elements for (var i = 0; i < myList.length; ...