Init 2D arry

Hi, I've figured out how to init an array on declaration:

myarray[] = [1,2,3]

But what is the syntax for a 2D array please:

myarray[][] = and then what?

Thanks.

myarray[][] = [ [1, 2, 3], [4, 5, 6], [7, 8, 9] ]

Thanks dude, I tried something like that but must have had it wrong!

that is an array of arrays, but it will work just fine, an actual 2D array cannot be auto-initialised.

http://www.blitzwiki.org/index.php/Arrays

Thanks for the link. So that's pretty weird then, I'm using an array of arrays not a 2D array and they can't be auto-initialised, weird!

does this work for you?

Global myArray:Int[][] = [[0,1,2,3],[9,10,11,12],[13,14,15,16]]

For Local x:Int = 0 To 2
	For Local y:Int = 0 To 3
		Print myArray[x][y]
	Next
Next

Look, everyone, I've never used Blitz Max, so I could be totally wrong about this, but wouldn't the best way to initialize an array be to use something like:

Dim MyArray(100,100)

Replacing the 100's with whatever number of elements you need? I mean, the only time I create an array in a variable is when I do it in a type field, like:

Type MyType
    Field ArrayField[100]
End Type

No, that would be one way to declare a 2D array in B2D or B3D.

To declare a 2D array in BMax you would do

Global myArray:Int[100,100]

But that's not the same as initializing it, since you can't auto-initialize a multi-dimensional array.

array of arrays needs to be initialized. a little more work but they are more flexible (can slice)

' =======2D Array=======
Local array[10,10]

array[2,2] = 4
Print array[2,2]

array[5,5] = 25
Print array[5,5]

' ==========Array of Arrays===========
Local GRID[][]
Local GridWidth:Int = 10
Local GridDepth:Int = 15

Grid = Grid[..GridWidth]

For Local count:Int = 0 To GridWidth - 1
		GRID[count] = Grid[Count][..GridDepth]
Next
	
GRID = GRID[..GridWidth][..GridDepth]



GRID[2][2] = 4
Print GRID[2][2]

GRID[5][5] = 25
Print GRID[4][4]

In the end I did this:

	Const GAP=20
	Field StarCoords%[][] = [[-GAP*2,0],[-25,GAP+4],[0,35],[25,GAP+4],[GAP*2,0]] 

and accessed with StarCoords[x][y]

Seemed fine.

Is this still supposed to work with the latest BlitzMax?
I could really use something like this, but when I try the above as-is it returns the error: Expected Expression but encountered '='

Global myarray[] = [1,2,3]

Or Local or Field

you better don't use that.
While this init look nice, its several times slower than

myarray[] = new int[3]
myarray[0] = 1
..
..


Seems like above is some kind of pseudo slicing mechanism doing the dynamic initialisation.

weird. However, most of the time it's for relatively tiny Arrays and the first method is nice and readable.

I used it with 3 elements (position vector and therefor called on each object creation 2-4 times) and it ate a fair amount of time ... (we are talking of a factor of 20+ here already with 3 elements)

But will have to retest, my test on this issue was quite some time ago, perhaps some internal changes happened to it that do remove the need to use per element init.

I agree that the "c style" is more readable.

wow that is a lot slower. My arrays like that are only initialised once on game init so it's a non-issue.