How do you declare a 2d array?

[Melba23]

mikell,

The differentiation between Map and Array declaration is already made clear in the 3.3.13.19 Beta Help file:

Both Arrays and Maps use similar syntax, so care is required to ensure the variable is of the correct datatype - this is determined by the first declaration line for the variable:

Using empty [ ] declares a Map:

----------------------------------------------------------
Local $vVar[] ; A Map 
----------------------------------------------------------

Filling the [ ] with a dimension size declares an Array:

----------------------------------------------------------
Local $vVar[3] ; An Array 
----------------------------------------------------------

Assigning element values when declaring makes the variable an Array - these three lines are functionally equivalent:

----------------------------------------------------------
Local $vVar[3] = [1, 2, 3] ; An Array
Local $vVar[] = [1, 2, 3] ; An Array
Local $vVar = [1, 2, 3] ; An Array 
----------------------------------------------------------

And as I said above, I will now add something to make clear that a scoping keyword is obligatory on declaration.

M23

[SmOke_N]

@Melba23, I must admit, 3 different ways to accomplish a "standardized method" is a bit concerning.  Especially if you leave one thing out or add one thing to, it's a different data type all together.

@OP, If you're unsure, just standardize your own coding.  Declare the array with a finite index.

Global $gaArray[1][1]

Manage your code:

<code>
<code>
<etc>
... I need to access my array
... I am now going to index my array with ReDim
<code>
<etc>
</code>

At the point you know your going to need to access the array, then ReDim it, to clear the array, just re-declare it (in the same scope it was created in).

It's worked for years before mapping structured arrays were introduced.

[Melba23]

SmOke_N,

 

3 different ways to accomplish a "standardized method" is a bit concerning

Nothing to do with me - all I do is write the documentation to try and explain it.

M23

[mikell]

Melba,

I already had a look to the beta helpfile, and said nothing more than I said - considering that like most of the OPs I use the 3.3.12.0 (the recommended one on the main download page) in which Maps don't exist yet 

Anyway the new helpfile will have to be very explicit to avoid confusion (headaches expected)

Local $test[]    ;declares a Map
Local $test[] = [1, 2, 3] ; An Array

$mMap[3] = "string"  ; fills a map key
$aArray[3] = "string"  ; fills an indexed element

[jchd]

All variables in AutoIt must use a scope specifier in their declaration, not only arrays.

What is special with arrays is that they must be declared with explicit dimension(s) or with explicit literal initialisation prior to use, irrespective of AutoItSetOption("MustDeclareVars", <setting>).

Also empty arrays can use [0] as the first dimension in declaration:

Local $a[0]    ; an empty 1D array with zero rows
Local $b[0][3] ; an empty 2D array with zero rows of 3 columns
Local $c[2][0] ; a problematic empty array of 2 rows with zero columns!!!

Edited February 21, 2015 by jchd