Understanding Arrays

[EniamaJ]

Ok i have a problem.

I am currently reading the help file and looking over code trying to understand and learn autoit but i am stuck on arrays.

i see the example in the help file which is

; Example 2 - Declaring arrays
Dim $weeklyWorkSchedule[$daysWorking]
Global $chessBoard[8][8]
Local $mouseCoordinates[2], $windowStats[4]

I dont seem to understand how they work, i know here it says Declaring which has to do with variables but i just dont know how they work.

Any kind of help and understanding will be a big help.

Thanks in advance

[scriptkitty]

Array 101

for a simple array, we will make one with 3 elements, give it some values and then display them with a for statement.

dim $array[3]; this made $array[0]  $array[1] and $array[2]
$array[0]=2
$array[1]="bob"
$array[2]="sam"
for $i=0 to 2
msgbox(1,"display $array[" & $i & "]",  $array[$i] ,5)
next

Same thing but with Stringsplit

$array=Stringsplit("bob,sam",","); this makes an array with comma delimiters.
for $i=0 to 2
msgbox(1,"display $array[" & $i & "]",  $array[$i] ,5)
next

you can also dimention arrays with variables.

$x=3
dim $array[$x]; this made $array[0]  $array[1] and $array[2]
$array[0]=2
$array[1]="bob"
$array[2]="sam"
for $i=0 to 2
msgbox(1,"display $array[" & $i & "]",  $array[$i] ,5)
next

They get complex if you need them too.

Edited March 11, 2004 by scriptkitty

[Wallfire]

hey, i had the same troubles with arrays. check out my help thread with arrays lots of people helped me out and you can prob find your answer in there

[scriptkitty]

These have to do with global values vs local values.

When using functions, you can have variables that only are in the function(LOCAL), or make them GLOBAL to the whole script.

Before you can add values to the elements of an array, you need to DIMention it (unless you use StringSplit which dimentions it at creation and assisgns the first element as the quantity of elements besides itself.)

Dim $array[3]

Global $array[3]

Local $array[3]

[Nutster]

What is happening in each of those statements is that chunks of memory are being set aside for the purpose of a set of variables, each one accessable using the array's name and the element's index number.

Dim $MyVar

This sets aside room for 1 variable, giving it the name MyVar. The variable is accessable by using the variable's name. i.e. $MyVar.

Dim $MyArray[12]

This sets aside room for 12 variables in an array, called MyArray. They are accessable using the array's name and the element's index number, which in this case could be any number from 0 through 11. Why throw away a perfectly good number like 0? They can be used very similarily after that; just do not assign a simple value to the array or you wipe it out.

$MyVar = "Test"

$MyArray[3] = "Test 2"

MsgBox(0, "Title", "$MyVar = " & $MyVar)

MsgBox(0, "Title", "$MyArray[3] = " & $MyArray[3])

[scriptkitty]

Nice explanation.

Here is something wierd to look at

Opt("MustDeclareVars", 0)      ;0=no, 1=require pre-declare
dim $array[2]
$array[0]=" there"
$array[1]=" Fred."
MsgBox(1,"Test1",$array&$array[0]&$array[1])
MsgBox(1,"Test2",$array[0]&$array[1])

[EniamaJ]

ok so its like

Dim $count[5]

$count[0] = 1

$count[1] = 2

$count[2] = 3

$count[3] = 4

$count[4] = 5

??

So arrays are like a variable with sorta like a drop down menu

but this seems to have me stuck

$chessBoard[8][8] how does that double thing work?

[scriptkitty]

A chessboard is an 8x8 grid. You could map out each chess piece with this array.

Been a while since I played chess but.

Dim $chessBoard[8][8]

$chessBoard[0][0]="rook"

$chessBoard[0][1]="bishop"

$chessBoard[0][2]="knight"

$chessBoard[0][3]="queen"

$chessBoard[0][4]="King"

$chessBoard[0][5]="knight"

$chessBoard[0][6]="bishop"

$chessBoard[0][7]="rook"

$chessBoard[1][0]="pawn"

$chessBoard[1][1]="pawn"

$chessBoard[1][2]="pawn"

$chessBoard[1][3]="pawn"

$chessBoard[1][4]="pawn"

$chessBoard[1][5]="pawn"

$chessBoard[1][6]="pawn"

$chessBoard[1][7]="pawn"

$chessBoard[2][0]=

$chessBoard[2][1]=

$chessBoard[2][2]=

$chessBoard[2][3]=

.....

$chessBoard[7][6]="bishop"

$chessBoard[7][7]="rook"

Edited March 11, 2004 by scriptkitty

[Jon]

ok so its like

Dim $count[5]

$count[0] = 1

$count[1] = 2

$count[2] = 3

$count[3] = 4

$count[4] = 5

??

So arrays are like a variable with sorta like a drop down menu 

but this seems to  have me stuck

$chessBoard[8][8] how does that double thing work?

Ever seen post trays or a big rack of mailboxes/pigeon holes that look like a big grid? That's pretty much an array. Each "hole" can contain something and is referenced by a name like John Doe or something. In computing terms we just use numbers instead.

[EniamaJ]

$Chess[5][5]

$Chess[0][0] = 11
$Chess[0][1] = 12
$Chess[0][2] = 13
$Chess[0][3] = 14
$Chess[0][4] = 15
$Chess[1][0] = 16
$Chess[1][1] = 17
$Chess[1][2] = 18
$Chess[1][3] = 19
$Chess[1][4] = 100
$Chess[2][0] = 111
$Chess[2][1] = 112
$Chess[2][2] = 113
$Chess[2][3] = 114
$Chess[2][4] = 115
$Chess[3][0] = 116
$Chess[3][1] = 117
$Chess[3][2] = 118
$Chess[3][3] = 119
$Chess[3][4] = 120
$Chess[4][0] = 121
$Chess[4][1] = 122
$Chess[4][2] = 123
$Chess[4][3] = 124
$Chess[4][4] = 125

Is that correct?

And the basic is

$Board[8]

$Board[0] = 2
$Board[1] = 3
$Board[2] = 4
$Board[3] = 5
$Board[4] = 6
$Board[5] = 7
$Board[6] = 8
$Board[7] = 9

[scriptkitty]

I like the stalls analagy.

If you were to write down names in a notebook:

Thinking about an analagy for 3.

1) $names[$how_many_lines_on_a_page]

2) $names[$how_many_lines_on_a_page][$how_many_pages_in_a_book]

3) $names[$how_many_lines_on_a_page][$how_many_pages_in_a_book][$how_many _books]

dim $names[$linenum][$pagenum][$booknum]

more useless array work:

store every pixel into an array
$begin = TimerStart()
Dim $pixel[@DesktopWidth][@DesktopHeight]

For $x=0 To @DesktopWidth-1
    For $y= 0 To @DesktopHeight-1
  $pixel[$x][$y]=PixelGetColor ($x,$y) 
    Next
Next

$dif = TimerStop($begin)
$pixel=0; release the memory
$pixels=@DesktopWidth*@DesktopHeight
MsgBox(1,"Time for "&$pixels&" pixels","Every pixel put into an array in "&int($dif/1000)&"seconds")

[sykes]

Ahhhh Grasshopper ... The Array student is now the Array master

[EniamaJ]

It is now your obligation to answer this question, the next time it arrives.... Congratulations... 

Thank you all for the help i appreciate it

I will toy around with this for a while befor i move on again thanks

[Nutster]

Here is something weird to look at

Opt("MustDeclareVars", 0)    ;0=no, 1=require pre-declare
dim $array[2]
$array[0]=" there"
$array[1]=" Fred."
MsgBox(1,"Test1",$array&$array[0]&$array[1])
MsgBox(1,"Test2",$array[0]&$array[1])

The problem here is referring to an array ($array) as a normal string variable, which is what is contained in $array[0] and $array[0]. This invalid reference seems to have caused to expression evaluator to bomb out, returning an empty string. Edited March 13, 2004 by Nutster