Question

How do you fill a NSMutableArray with a set capacity for later use?

Basically I want to set up a NSMutableArray to act as a map for my game objects, so I have this line…

gameObjects = [[NSMutableArray alloc] initWithCapacity:mapWidth*mapHeight];

Which I had hoped would create and fill my MutableArray so I can get then access it with this kind of index…

int ii = (cellY*mapWidth)+cellX;

NSDictionary *currentObject = [gameObjects objectAtIndex:ii];

But I just learned initWithCapacity doesn’t fill the array, so should I create blank objects to fill it with, or is there a Null that I can fill it with? Also would I do that with 2 for loops or is there an instruction something like “initWith:myObject” ?

I want to be able to check at a certain index within the array to see if there’s an object there or not, so I need to be able to acces that index point, and I can only do that if there’s something there or I get an out of bounds error.

I’ll be using this NSMutableArray pretty much as a grid of objects, it’s a 1 dimensional array organised as a 2 dimensional array, so I need to be able to fill it with mapWidth*mapHeight of something, and then calculate the index and do a check on that index within the array.

I’ve looked on here and googled but couldn’t find anything like what I’m asking.

Thanks for any advice.

Answer 1

I think what you are looking for is [NSNull null]. It is exactly what you want- a placeholder value.

You can find more information on the topic in this question.