arrays - Error on AS3: TypeError: Error #1010: A term is undefined and has no properties -

i'm trying create collision code involving array of bullets , array of zombies. when tried code:

    for(var bu:int = 0;bu < bullets.length; bu++){         for(var zo:int = 0;zo < zombiecount.length; zo++){             if(bullets[bu].hittestobject(zombiecount[zo])){                 stage.removechild(zombiecount[zo]);                 zombiecount.splice(zo, 1);                 stage.removechild(bullets[bu]);                 bullets.splice(bu, 1);                  trace("hot hit")             }         }     } 

i error message. tried code:

    for(var bu:int = 0;bu < bullets.length; bu++){         for(var zo:int = 0;zo < zombiecount.length; zo++){             if(bullets[bu].hittestobject(zombiecount[zo])){                 stage.removechild(zombiecount[zo]);                 if(zombiecount.splice(zo,1)!=null){                     zombiecount.splice(zo, 1)                 }                 stage.removechild(bullets[bu]);                 bullets.splice(bu, 1)                 if(bullets.splice(bu,1)!=null){                     bullets.splice(bu, 1)                 }                                trace("hot hit")             }         }     } 

however, though message doesn't appear, objects(or rather remains?) stops there. if go original code, i'll keep receiving error messages. please help.

most issue because of 2 things:

1. you're splicing array inside loop iterates on said array forwards.

   if you're going this, should iterate backwards doesn't mess index.

for example, let's zombiecount has 3 elements. first iteration zo = 0, let's hit test succeeds, splice array, zombiecount has 2 elements. next iteration, zo=1, item used referenced zombiecount[1] in zombiecount[0] now. you've ended skipping item.

2. you remove bullet, don't break out of inner loop (that loops through zombies) - problem here if more 1 zombie touching bullet, you'll end trying remove bullet multiple times , un-intentionally splicing different bullets out of array. error because @ point index bu becomes out of range result of issue.

for exmaple, let's bullets array has 2 elements , zombie array has 3 elements. first iteration bu 0, let's hittest succeeds on first zombie in array. splice bullets, has 1 element. let's second zombie in array passes hittest. splicing bullets again, except it's second item ends getting spliced. let's third zombie in array passes hitest too, there nothing left in bullets array, trying splice anyway , remove non-existent object stage.

try instead:

//iterate backwards, if remove item array, it's last item , won't throw off order of array for(var bu:int = bullets.length-1;bu >= 0; bu--){     for(var zo:int = zombiecount.length-1;zo >= 0; zo--){         if (bullets[bu].hittestobject(zombiecount[zo])) {             //remove zombie             stage.removechild(zombiecount[zo]);             zombiecount.splice(zo, 1);              //remove bullet             stage.removechild(bullets[bu]);             bullets.splice(bu, 1);              trace("hot hit");              break; //break out of inner loop (through zombies), since bullet has been destroyed         }     } }