Understanding Arrays

[tes5884]

Hi Guys,

I'm having a hard time wrapping my brain around Arrays. Specifically, multi-dimensional, as well as dimension and entry limits.'

I already read the AutoIt docs page a couple of times.

Anyone have a better explanation and/or links?

Thanks!

[water]

The wiki has a very good tutorial describing how arrays work.

[Melba23]

tes5884,

I recommend the Arrays tutorial in the Wiki. Please post again if you still have questions.

M23

[tes5884]

Thank you both. I didn't notice that one.

[Mechaflash]

x axis VS x + y axis VS x + y + z axis

Remember in geometry when you had to calculate distances in a 3 dimensional object? you had your x,y, and z axis. Same idea.

x = rows

y = columns

z = depth

Local $array[1] ; single dimension array with 1 element

Local $2D[1][2] ; two dimensional array with 2 indexes and 1 element in each index.
; i.e. $2D[0][0], $2D[0][1]

Local $3D[1][2][2] ; three dimensional array with 2 planes, 2 indexes on each plane, and 1 elements in each index
; i.e. $3D[0][0][0], $3D[0][1][0], $3D[0][0][1],  $3D[0][1][1]

[Spiff59]

Looking at it one way, the number of dimensions is almost meaningless.

It's just another way of labelling the same variables or "mailboxes" that you're creating.

$aArray[24] is the same thing as $aArray[3][8] (3 x 8 = 24) which is the same thing as $aArray[3][2][4] (3 x 2 x 4 = 24).

They are all just a table of 24 variables.

If your 3-story apartment building has 24 units and you just want to store all the apartment numbers then use $aArray[24] (apt#).

If you want to organize them by floor you could create the same 24 boxes but reference them as $aArray[3][8] (floor/apt#)

If you had a reason to keep the apartments on the north side of the building separate from those on the south side, then you could setup your 24 mailboxes as $aArray[3][2][4] (floor/north-south/apt#)

When you reference the 17th element of the 1-dimension array; $aArray[17], it is the same thing internally as referencing element $aArray[2][0][1] of the 3-dimension array (2 x 8 + 0 x 4 + 1 x 1 = 17)

Hope I haven't made things worse

Edit: You could simulate any number of dimensions using a 1-dimension array and a few lines of code. This is, at least conceptually, the same thing that goes on internally when you decide to split your array into different dimensions:

Global $aApartments[24] = ["1A","1B","1C","1D","1E","1F","1G","1H","2A","2B","2C","2D","2E","2F","2G","2H","3A","3B","3C","3D","3E","3F","3G","3H"]

MsgBox(0, "1-Dimension", Dimension_Simulator("24", "17")) ; get element [17] of $aArray[24]
MsgBox(0, "2-Dimension", Dimension_Simulator("3*8", "2|1")) ; get element [2][1] of $aArray[3][8]
MsgBox(0, "3-Dimension", Dimension_Simulator("3*2*4", "2|0|1")) ; get element [2][0][1] of $aArray[3][2][4]

Func Dimension_Simulator($structure, $element)
    Local $aStructure = StringSplit($structure, "*")
    Local $iSize = Execute($structure) ; total elements

    Local $aElement = StringSplit($element, "|")
    Local $iTarget
    For $x = 1 to $aElement[0] ; calculate element offset
        $iTarget += $aElement[$x] * ($iSize / $aStructure[$x])
     $iSize /= $aStructure[$x]
    Next
    Return $aApartments[$iTarget]
EndFunc

Edited August 11, 2012 by Spiff59

[tes5884]

Alright, I have lot's of homework now I'll keep you guys posted. Thanks!!!

[tes5884]

Question; if I have a variable

toast = $var[2][2]

Does that mean I can have values like the following;

$var[0][0]

$var[0][1]

$var[0][2]

$var[1][0]

$var[1][1]

$var[1][2]

$var[2][0]

$var[2][1]

$var[2][2]

or am I missing something?

Thanks!!!

Edited August 13, 2012 by tes5884

[water]

Your list of array elements is correct.

Array elements always start with an index of 0. If you have an $array[7] the index goes from 0 to 6 (or "UBound($array, 1) - 1)".

[tes5884]

Your list of array elements is correct.

Array elements always start with an index of 0. If you have an $array[7] the index goes from 0 to 6 (or "UBound($array, 1) - 1)".

Does index 0 hold a comparable value to any other number?

In other words, does the first index (0), point to an element just like any other index ? or is it any different.

[water]

Depends on how the array was created. It's often referred to as "zero-based" or "one-based". Means the data starts in row 0 or row 1. If it starts in row 1 then row 0 contains the number of rows.

If it is a two dimensional array then $array[0][0] contains the number of rows and $array[0][1] contains the number of columns.

Check function StringSplit as an example. You can decide if the function returns a zero- or one-based array.

[Mechaflash]

It's just like any other index.

Many functions that return an array (_FileListToArray()) use the 0 index to hold specific information. In the case of _FileListToArray(), the 0 index holds the total file/folder count. For these functions you can iterate over them as follows:

For $i = 1 To $array[0]
    msgbox(0,"",$array[$i])
Next

For 0-based arrays, you can iterate over them as:

For $element in $array
    msgbox(0,"",$element)
Next

[tes5884]

Got it. Thanks water and mechaflash213.

Edited August 13, 2012 by tes5884