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blumi

Create array in a loop

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How to create an array in a loop?

I don't know how many values are added to the array.

Do I have to create the array before start of the loop or do I create it in the loop?

Thanks

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Like this...the key is ReDim. You should have a basic understanding of Arrays before you continue.

#include <Array.au3>

Example()

Func Example()
    Local $aArray[1] = [0] ; 0th index holds the number of items in the Array.

    For $i = 1 To 100
        $aArray[0] += 1 ; Increase the total count by 1 as we're going to add another value.
        ReDim $aArray[$aArray[0] + 1] ; Increase the array by 1 to accomodate the new value (but look at _ReDim in my signature.)
        $aArray[$aArray[0]] = $i ; Since we've increased the count by 1, add the data to that index.
    Next
    _ArrayDisplay($aArray)
EndFunc   ;==>Example

Also look in my signature at _ReDim it tells you how to increase the size of an array effectively without affecting performance.


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Updated: 04/09/2015

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blumi,

At all costs avoid using ReDim on each pass through the loop - it is a really slow function, especially when arrays get big.

Here is a good way to create an array of unknown size in a loop - double the array size when necessary and then trim the unfilled elements at the end: :oops:

#include <Array.au3>

; Declare the array with a count
Global $aList[1] = [0]

; This is what we start with
_ArrayDisplay($aList, "Start")

For $i = 1 To 25

    ; Increase count
    $aList[0] += 1
    ; Double array size if too small (fewer ReDim needed)
    If UBound($aList) <= $aList[0] Then
        ReDim $aList[UBound($aList) * 2]
    EndIf
    ; Add item
    $aList[$aList[0]] = "Item " & $i

Next

; This is what we get after the loop
_ArrayDisplay($aList, "Filled")

; Now get rid of any unfilled elements
ReDim $aList[$aList[0] +1]

; And here is the result
_ArrayDisplay($aList, "Trimmed")

If you have some idea of the final size of the array, you can declare it with a much larger initial value - uses even fewer ReDims then. :bye:

M23


Any of my own code posted anywhere on the forum is available for use by others without any restriction of any kind._______My UDFs:

Spoiler

ArrayMultiColSort ---- Sort arrays on multiple columns
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GUIExtender -------- Extend and retract multiple sections within a GUI
GUIFrame ---------- Subdivide GUIs into many adjustable frames
GUIListViewEx ------- Insert, delete, move, drag, sort, edit and colour ListView items
GUITreeViewEx ------ Check/clear parent and child checkboxes in a TreeView
Marquee ----------- Scrolling tickertape GUIs
NoFocusLines ------- Remove the dotted focus lines from buttons, sliders, radios and checkboxes
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StringSize ---------- Automatically size controls to fit text
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#4 ·  Posted (edited)

Directly taken from my article, 5000 items added to an Array, time is in milliseconds.

9015.65737361414 ; Increasing by 1 everytime.

76.3449705440588 ; Effectively increasing when required and by multiplying the size by 2, as suggested by Melba23.

You can see the difference is quite substantial. Edited by guinness

_AdapterConnections()_AlwaysRun()_AppMon()_AppMonEx()_BinaryBin()_CheckMsgBox()_CmdLineRaw()_ContextMenu()_ConvertLHWebColor()/_ConvertSHWebColor()_DesktopDimensions()_DisplayPassword()_DotNet_Load()/_DotNet_Unload()_Fibonacci()_FileCompare()_FileCompareContents()_FileNameByHandle()_FilePrefix/SRE()_FindInFile()_GetBackgroundColor()/_SetBackgroundColor()_GetConrolID()_GetCtrlClass()_GetDirectoryFormat()_GetDriveMediaType()_GetFilename()/_GetFilenameExt()_GetHardwareID()_GetIP()_GetIP_Country()_GetOSLanguage()_GetSavedSource()_GetStringSize()_GetSystemPaths()_GetURLImage()_GIFImage()_GoogleWeather()_GUICtrlCreateGroup()_GUICtrlListBox_CreateArray()_GUICtrlListView_CreateArray()_GUICtrlListView_SaveCSV()_GUICtrlListView_SaveHTML()_GUICtrlListView_SaveTxt()_GUICtrlListView_SaveXML()_GUICtrlMenu_Recent()_GUICtrlMenu_SetItemImage()_GUICtrlTreeView_CreateArray()_GUIDisable()_GUIImageList_SetIconFromHandle()_GUIRegisterMsg()_GUISetIcon()_Icon_Clear()/_Icon_Set()_IdleTime()_InetGet()_InetGetGUI()_InetGetProgress()_IPDetails()_IsFileOlder()_IsGUID()_IsHex()_IsPalindrome()_IsRegKey()_IsStringRegExp()_IsSystemDrive()_IsUPX()_IsValidType()_IsWebColor()_Language()_Log()_MicrosoftInternetConnectivity()_MSDNDataType()_PathFull/GetRelative/Split()_PathSplitEx()_PrintFromArray()_ProgressSetMarquee()_ReDim()_RockPaperScissors()/_RockPaperScissorsLizardSpock()_ScrollingCredits_SelfDelete()_SelfRename()_SelfUpdate()_SendTo()_ShellAll()_ShellFile()_ShellFolder()_SingletonHWID()_SingletonPID()_Startup()_StringCompact()_StringIsValid()_StringRegExpMetaCharacters()_StringReplaceWholeWord()_StringStripChars()_Temperature()_TrialPeriod()_UKToUSDate()/_USToUKDate()_WinAPI_Create_CTL_CODE()_WinAPI_CreateGUID()_WMIDateStringToDate()/_DateToWMIDateString()Au3 script parsingAutoIt SearchAutoIt3 PortableAutoIt3WrapperToPragmaAutoItWinGetTitle()/AutoItWinSetTitle()CodingDirToHTML5FileInstallrFileReadLastChars()GeoIP databaseGUI - Only Close ButtonGUI ExamplesGUICtrlDeleteImage()GUICtrlGetBkColor()GUICtrlGetStyle()GUIEventsGUIGetBkColor()Int_Parse() & Int_TryParse()IsISBN()LockFile()Mapping CtrlIDsOOP in AutoItParseHeadersToSciTE()PasswordValidPasteBinPosts Per DayPreExpandProtect GlobalsQueue()Resource UpdateResourcesExSciTE JumpSettings INISHELLHOOKShunting-YardSignature CreatorStack()Stopwatch()StringAddLF()/StringStripLF()StringEOLToCRLF()VSCROLLWM_COPYDATAMore Examples...

Updated: 04/09/2015

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