Array的使用技巧
There are many instances when you might want to loop through all the elements of an array. For example, by looping through an array containing references to sprites, you can perform a particular action on each of the sprites:
for (var i:int = 0; i < sprites.length; i++){ // Move each sprite one pixel to the right. sprites[i].x++;}
You can store the array's length in a variable rather than computing it during each loop iteration. For example:
var length:int = sprites.length;for (var i:int = 0; i < length; i++){ // Move each sprite one pixel to the right. sprites[i].x++;}
The effect is that there is a very marginal performance improvement because Flash doesn't have to calculate the length during each iteration. However, it assumes that you are not adding or removing elements during the loop. Adding or removing elements changes the length property. In such a case, it is better to calculate the length of the array with each iteration.
public native function splice(startIndex:int, deleteCount:uint, ... values):Array;