How to removechild in as3? - actionscript-3

Question

this is my code:
var star:Sprite = new Sprite();
for (var i:Number = 0; i<50; ++i) //check if sky contains star , remove them
{
if (sky.contains(star)) //this "if" didnt work!
{
sky.removeChild(star);
}
}
for (i= 0; i<50; ++i) //add new stars to sky
{
star = new Sprite();
star.graphics.beginFill(0xFFFFFF);
star.graphics.drawCircle(0, 0, ((Math.random() * 1.5) + 0.25));
star.x = Math.random() * stage.stageWidth ;
star.y = Math.random() * stage.stageHeight;
sky.addChild(star);
}
the 1st "if" didnt work and in 2nd "for" stars add to sky over previous stars! what is the correct code to remove previous stars?thanks

Answer 1

Use this remove stars from the sky. It will remove all objects from sky.
for (var i:Number = 0; i < sky.numchildren; ++i)
{
sky.removeChildAt(i);
}
If you want to remove only stars from the sky , declare a new class for star
for (var i:Number = 0; i<sky.numchildren; ++i)
{
if(sky.getChildAt(i) is Star){
sky.removeChildAt(i);
}
}

Answer 2

As #DodgerThud said in his comment, it's better to use an array to store your stars for this portion of your code and may be for others operations you will do / need in next steps, so you can do like this :
var star:Sprite,
stars:Array = [], // array to store our stars
i:int;
for (i = 0; i < stars.length; i++)
{
Sprite(stars[i]).parent.removeChild(stars[i]);
}
stars = [];
for (i = 0; i < 50; i++)
{
star = new Sprite();
star.graphics.beginFill(0xFF00FF);
star.graphics.drawCircle(0, 0, ((Math.random() * 1.5) + 0.25));
star.x = Math.random() * stage.stageWidth ;
star.y = Math.random() * stage.stageHeight;
stars.push(star); // store your star into the stars array
sky.addChild(star);
}
Hope that can help.

Answer 3

you should use while loop instead of if here.
// that removes all the childs
while(sky.numChildren > 0){
sky.removeChildAt(0);
}
// if you want to keep just 1 clip
while(sky.numChildren > 1){
sky.removeChildAt(0);
}

Answer 4

Assuming you are going to remove all stars from the sky and:
Sky is also a sprite or subclass of sprite
Your sky only contains stars and nothing else
You want to clear all stars from the sky and then add them back.
Hope this helps.
var stars:Array = new Array();
for(var i:int=0; i<sky.numChildren; ++i)
{
sky.removeChild(sky.getChildAt(i));
}
if(stars.length == 0) //create stars if not created before
{
for (i= 0; i<50; ++i)
{
var star:Sprite = new Sprite();
star.graphics.beginFill(0xFFFFFF);
star.graphics.drawCircle(0, 0, ((Math.random() * 1.5) + 0.25));
star.x = Math.random() * stage.stageWidth ;
star.y = Math.random() * stage.stageHeight;
stars.push(star);
}
}
//add all stars created to sky
for each(var _star:Sprite in stars)
{
sky.addChild(_star);
}