[RESOLVED] how to create multidimensinal arrays? AS3

var test:Array = new Array();

test[1][55][10][38] = "some value"; //is not working
test[2] = "value"; //is working

Though I think this code will work for retrieving data from multidimensional array:
trace(test[1][55][10][38]);

I just do not know how to make one.

Here you go:

var ar:Array=[1,2,[3,4,5]];
trace("Array: ",ar,"\nArray element 0:", ar[0], "\nArray element 1:", ar[1], "\nArray Element 2:", ar[2], "\nFirst Element of Array Element 2: ", ar[2][1]);

EDIT: Oops, I think I missed what you wanted.
First, you can do like ar[2]=[3,4,5];

You can also do something like

var ar=new Array(6);
for (var i=0; i<ar.length; i++){
ar[i]=new Array(6);
}

Then, you can access it like ar[2][3]=5;

Ok, so I have to make 4 loops if I need 4-dimension array?
And CPU has to loop through all of it just to do simple
var arr dim(100,100,1000,5);


What a lovely, lovely language ;)

Maybe there is a better way. You bring up a very good point.

Unfortunately that better way is not mentioned in Adobe's documentation/techsupport (or at least in the 2 pieces that I read).

This is a bit depressing. Hopefully someone knows of better way. Then again, I do not think Flash was meant to deal with arrays that big.

By the way, why do you need such a big array?

Not really. You just need to define each level as an array, that's the only problem.

If you call: test[1][55][10][38] = "some value";

What is test[1][55] ? What if it was a Number? Or a String?

Each level needs to be declared as an array first.

test = new Array();
test[1] = new Array();
test[1][55] = new Array();
test[1][55][10] = new Array();
test[1][55][10][38] = "some value";

If you do that though, what if you want to access test[1][54][3][39]? (or anything else but test[1][55][10][38]? It does not work... I think that is what OP wanted (namely being able to access everything in the array, not just a few elements)...but I may also be wrong on that.

You are right. The other elements are inaccessible.

It'd help if I knew the purpose of needing such a large dimensional array. I've never seen the use of anything more than [x][y][z].

I am making a tile based game... And I figure that Array is fastest way to deal with huge amount of data. So my thoughts was like this:

Arr[i][j][k][l]

i =number of "objects"
j*k = defines space like x*y coordinates
l = value/bmp that gets drown on screen but l will change its value sometimes

Quote:

---

What is test[1][55] ? What if it was a Number? Or a String?

---

That was my whole point:
if I create test[1][55][10][38] = "some value";

trace(test[1][55]) is meaningless! You can not access 4 dim array by 2dim reference!

So, how do you create [x][y][z] array?

I just tested what sphoenixee suggested. It is horribly slow at creating but it works.

Quote:

---

var niz:Array = new Array();

for(var i:uint = 0; i < 10000; i++)
{

niz[i] = new Array();
for(var j=0;j<100;j++)
{
niz[i][j] = new Array();
for(var k:int = 0; k<10;k++)
niz[i][j][k] = k;
}
}

---

That makes niz:Array of 10000*100*10. And I can add values like this: niz[x][y][z] = "value";

We solved it. Kind of... But it really sucks :(

This is crazy overkill...set up a simple x by y two-dimension array.

test[x].length will give you the number of columns you have, test[x][y].length is the number of rows in a given column (there's nothing in the code that says all columns will be the same length...)

For the value to draw on screen...either store that as a property of the sprite/mc/tile or else use a dictionary...ie:

var terrain_by_sprite:Dictionary = new Dictionary();
terrain_by_sprite[test[x][y]] = "dirt";

Also, lower level languages such as C simply reserve a linear block of memory equivalent to the product of all dimensions. That is to say a 5x3 2 dimensional array is equivalent to a 15 element one dimensional array. You can manually determine the 1 dimensional equivalent address by multiplying the size of each dimension. something[5][4][3] in a 3 dimensional(10x11x12) array could be something2[5*11*12 + 4*12 + 3].

I think. I'm not 100% sure on that math at the end.

Quote:

---

Originally Posted by neznein9

test[x].length will give you the number of columns you have, test[x][y].length is the number of rows in a given column (there's nothing in the code that says all columns will be the same length...)

---

Ok, but how to make var test:Array of 100*1000 elements?

Quote:

---

Originally Posted by neznein9

For the value to draw on screen...either store that as a property of the sprite/mc/tile or else use a dictionary...ie:

var terrain_by_sprite:Dictionary = new Dictionary();
terrain_by_sprite[test[x][y]] = "dirt";

---

It will be sprite :)

@5TonsOfFlax:
Yes! I googled your post earlier. It could be done that way and your math is right.
something2[5*11*12 + 4*12 + 3].

array.length = length*height*width; //basically a stream of data

array[ (x) + (length * y) + (length * height * z)];
where x has to be x < width

Well, you could get away with a single loop to build the structure:

PHP Code:

---

const cols:int = 100;
const rows:int = 1000;

while(rows > 0){
    rows--;
    test.push(new Array(cols));    
} 


---

But you'd still need a double loop to touch each cell to populate:

PHP Code:

---

const cols:int = 100;
const rows:int = 1000;

while(rows > 0){
    rows--;
    while(cols > 0){
        cols--;
        test[rows].push(new Sprite());
    }    
} 


---

Thanks neznein9, that's similar to post #9.


@5TonsOfFlax:

I tried timing single array and math approach. It's a little slower that [x][y] access.
If you have 4D array, math gets really hard to read because you have to add and multiply all that dimensions.

Oh, I realized that I was multiplying IN the loop!!! length * height could be hard coded as a number or one variable!!!
And, there's usage or int. It's fast for + - but slow for *.
Maybe number will be faster!

As expected putting premultiplied variable was a success! 30ms gain :)
int was faster than Number by few milliseconds.

EDIT:

I have to correct myself. 2D and 3D array access is FASTER by 5TonsOfFlax math!

680ms for array[x][y] vs. 640ms for array[math***) on average per million loops.

Glad to hear that it works out for you. I'd actually probably make the sacrifice and create a real multidimensional array in my code unless it was extremely performance bound. I just value logical structure and readability more than a few milliseconds.

One notable exception is the ByteArray returned by BitmapData.getPixels, which is already a 1d array representing the 2d image data.

Quote:

---

Originally Posted by 5TonsOfFlax

Glad to hear that it works out for you. I'd actually probably make the sacrifice and create a real multidimensional array in my code unless it was extremely performance bound. I just value logical structure and readability more than a few milliseconds.

---

I'll second this. In my experience with testing 2d and 3d arrays, while constructing a multidimensional array takes longer using it is faster.
As well, dropping in an 80 character operation for every lookup is a pain in the ass to maintain and code. Overlaying a function call to do it for you makes things easier but completely destroys performance.

Thank you all for helping. I'll use 2.5D array ;) Only AS3 allows that :D

Yet I still can not believe that I have to use loops to create arrays. Goes with a job I guess...