Populating Array of Unknown Size

[DarkDeveloper]

This is what I have so far and it works. I wasn't sure if there is a better way to do this. Next step is going to be getting display name and uninstall key. I just wanted to make sure that this is a good way to do the task I am attempting before continuing.

Func _uninstallProgram()

;reg to start at
Local $regamount = 1

;get the number of reg

While RegEnumKey("HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall", $regamount)

$regamount += 1



WEnd

;View error while loop stops on, should be -1 if all reg counted
MsgBox(0,"","Array Size: " & $regamount & " Error: " & @error)

;declare array size
Local $array[$regamount]

;populate array with list of reg names
For $i=0 to $regamount - 1

$array[$i] = RegEnumKey("HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall", $i)

Next

;check that list populated
_ArrayDisplay($array)

EndFunc

[water]

If it works and it is fast enough then you are fine.

If it is too slow we can show you how to speed up the code.

[Shaggi]

You can use _ArrayAdd() so you dont have to enumerate the registry two times. This might be a bit slow for large amounts of data, since the array is resized every time - you could maybe modify the function so the array grows by, say, 1.3 * size when full.

[DarkDeveloper]

There is only 400ish registries per computer. It will grow as more MS updates come but shouldn't be too bad. I do see what you mean Shaggi. I'll tweak with the logic a bit. The first one is just to get the number of registries that exist so I can declare an array size. I'll play around with some other things and if it slows down I will let you know.

[Melba23]

DarkDeveloper,

Take a look at the final script (and following explanation) in the Recursion tutorial in the Wiki - it shows how you can fill an array of unknown size with the minimum number of ReDim calls.

M23

[Spiff59]

Memory is nothing anymore...

Just set a large array up front and Redim() it once at the end (which frees the unneeded memory).

Throw in an error message in case anyone ever gets close to overflowing the table.

#include <Array.au3>
Global $iMaxArray = 2500, $array[$iMaxArray + 1]
_uninstallProgram()
_ArrayDisplay($array)

Func _uninstallProgram()
For $i = 1 to $iMaxArray
     $array[$i] = RegEnumKey("HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionUninstall", $i)
     If @error Then ExitLoop
Next
If $i > $iMaxArray Then
     MsgBox(16, "Error", "Maximum table size exceeded.")
Exit
EndIf
$array[0] = $i - 1
ReDim $array[$i]
EndFunc

Edit: Realistically, you could preset the array to a million elements and it might temporary allocate 20MB of memory until it hits the ReDim() and frees it up. For a wimpy PC with just a measly 1GB that's still only a temporary allocation of 2% of it's memory. Presetting it to anywhere from 1000 to 5000 won't even cause a PC to skip a beat.

Edited August 6, 2012 by Spiff59

[DarkDeveloper]

I looked at the recursion page but I don't think it will work since I cannot check for a next registry. However I did do this instead which works and should be more friendly to the part I am doing next.

expandcollapse popup

Func _uninstallProgram($programName)

Local $array[20]

$array[0] = UBound($array,1)

MsgBox(0,"",$array[0])

$i = 1

Do

$array[$i] = RegEnumKey("HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall", $i)

If StringCompare ($array[$i], "") = 0 Then

MsgBox(0,"","Blank Spot at " & $i)

ReDim $array[$i]

ExitLoop

ElseIf $i = $array[0]-1 Then

ReDim $array[UBound($array,1) * 2]

$array[0] = UBound($array,1)

MsgBox(0,"",$array[0])

EndIf

$i += 1

Until $i >= $array[0]

ReDim $array[UBound($array,1)]



MsgBox(0,"",@error)

_ArrayDisplay($array)

EndFunc

[elektron]

Check out my topic (I actually just posted this), that has a #include that you can use for a stack data structure. It'll work pretty well, and after you're done using it, you can just call a function and it will return an array for you to use.

[nullschritt]

Idk if this is a stupid idea, but you could just store all the values in a string and separate them with a character, say "|", then use stringsplit? (this way it would automatically size the array, and only have to enum once)

Local $regamount = 1
Local $keys = ''
do
$key = RegEnumKey("HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionUninstall", $regamount)
$keys &= $key&'|'
$regamount += 1
until @error
$array = stringsplit($keys, '|')

Edit: working example

Edited August 7, 2012 by nullschritt