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generate random string using regex as template

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That sounds terribly complicated with all the possible patterns.

An engine I'd not even remotely begin to take on myself.

Common sense plays a role in the basics of understanding AutoIt... If you're lacking in that, do us all a favor, and step away from the computer.

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Maybe something like this.

Local $sREPattern = "[0-9_a-zA-Z\r]+"

Local $my_random_string = randregex($sREPattern)
ConsoleWrite($my_random_string & @LF)
ConsoleWrite(StringLen($my_random_string) & " characters <<<<<<<" & @LF)

MsgBox(0, 'Check random string against pattern', StringRegExp($my_random_string, $sREPattern))

Func randregex($sPattern)
    Local $i = Random(1, 100, 1) ; Random length of string
    Local $iCount = 0, $sChar, $sRetStr
    ;ConsoleWrite($i & @LF)
    While $iCount < $i
        $sChar = ChrW(Random(0, 255, 1))
        If StringRegExp($sChar, $sPattern) Then
            $iCount += 1
            $sRetStr &= $sChar
    Return $sRetStr
EndFunc   ;==>randregex

Edit: Moved $iCount += 1 to within "If Then EndIf" statement; &
Changed $sChar = Chr(Random(32, 126, 1)) to $sChar = ChrW(Random(0, 255, 1)) in order to have every character available.

Edited by Malkey
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Malkey's way is certainly simplest, doesn't really play into specifics of a regex random string generator without specifics.

I started messing around with the concept, and I can now tell you.. I 100% would not attempt it.  Just messing with your single bracket expression made my head hurt when I thought of all the other possible regular expression combinations.

Here's an example:

#include <Array.au3>
; please note you have your A-z probably wrong, but I'm leaving it just in case it was intentional
Global $gsRet = _myCustomRandomGen("[0-9_a-zA-Z]+", 22)
ConsoleWrite($gsRet & @CRLF)

Func _myCustomRandomGen($sExpression, $nStrLen, $nEncoding = 0); see StringFromAsciiArray for encoding

    If $nStrLen < 1 Then
        Return SetError(1, 0, "")

    ; only deal with square bracket
    Local $aBrackets = StringRegExp($sExpression, "^(?!\\)\[(?!^)(.+?)(?!\\)\]", 3)
    If @error Then
        ; no square brakets
        Return SetError(2, 0, "")

    Local $aMatch = 0, $aTmp
    Local $aTo[10][2], $iCc
    For $i = 0 To UBound($aBrackets) - 1
        ; match x-x chars
        $aMatch = StringRegExp($aBrackets[$i], "(.-.|.)", 3)
        If @error Then ContinueLoop
        For $j = 0 To UBound($aMatch) - 1
            ; manage our dynamic array size
            If $iCc And Mod($iCc, 10) = 0 Then
                ReDim $aTo[$iCc + 10][2]
            ; extract from / to and single chars
            $aTmp = StringRegExp($aMatch[$j], "(?:(.)-(.)|(.))", 1)
            If @error Then ContinueLoop
            If UBound($aTmp) = 3 Then
                $aTo[$iCc][0] = AscW($aTmp[2])
                $aTo[$iCc][1] = $aTo[$iCc][0]
                $aTo[$iCc][0] = AscW($aTmp[0])
                $aTo[$iCc][1] = AscW($aTmp[1])
            $iCc += 1

    ; if we had nothing in the brackets, escape
    If Not $iCc Then
        Return SetError(3, 0, "")

    ; trim ubound of array based on matches
    ReDim $aTo[$iCc][2]

    ; ascii container
    Local $aRet[100]

    $iCc = 0
    For $i = 0 To UBound($aTo, 1) - 1
        For $j = $aTo[$i][0] To $aTo[$i][1]
            If $iCc And Mod($iCc, 100) = 0 Then
                ReDim $aRet[$iCc + 100]
            $aRet[$iCc] = $j
            $iCc += 1

    ; trim the array
    ReDim $aRet[$iCc]

    ; ensure array is at least as large as tring wanted
    If $iCc < $nStrLen Then
        $aTmp = $aRet
        While UBound($aRet) < $nStrLen
            _ArrayConcatenate($aRet, $aTmp)

    ; randomly shuffle the array

    ; trim to the stringlen we need
    ReDim $aRet[$nStrLen]

    Return StringFromASCIIArray($aRet)

Keep in mind, I didn't test past your single expression.


Had to ensure array size was at least string length wanted... oops!

Edited by SmOke_N

Common sense plays a role in the basics of understanding AutoIt... If you're lacking in that, do us all a favor, and step away from the computer.

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This would be very, very, very hard to accomplish algorithmically for an unknown pattern in a finite time.

My first thought was a brute force random string generator that would, in a flat universe without heat death, reach a solution in a finite time for any given pattern, but then I realized that there is an infinite amount of possible patterns that are unmatchable, like ^(?=y)x$ . So any brute force approach for one of those would mean an infinite loop. To fix this problem means to be able to algorithmically recognize any unmatchable pattern as such in a finite time, which seems like a daunting task in logic, to set the Guinness record for understatement.

But you're not the first one to try:

https://github.com/asciimoo/exrex/blob/master/exrex.py (Python)

https://github.com/mifmif/Generex (Java)

If you accept possible infinite loops and keep your supported regular expression feature set relatively modest (no lookaheads/lookbehinds for instance, they complicate things a lot) it's fairly doable. Still, I have better things to do :D

Edited by SadBunny

Roses are FF0000, violets are 0000FF... All my base are belong to you.

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As far as there is a single explicit character class involved, things can be made pretty simple, even if we optionally allow characters in the whole Unicode range that AutoIt handles:

Local $sPattern = "(*UCP)[0-9_a-zA-Z\p{Greek}]+"

Local $my_random_string

For $i = 1 To 10
    $my_random_string = randregex($sPattern, Random(8, 15, 1),True)
    msgbox(0, '', ">" & $my_random_string & "<" & @LF & StringRegExp($my_random_string, $sPattern))

Func randregex($sPattern, $iLength = 8, $bUnicode = False)
    Local Static $sChars = ""
    If $sChars = "" Then
        For $i = 0x20 To ($bUnicode ? 0xFFFF : 0xFF)
            If $bUnicode And $i = 0x80 Then $i = 0xA0
            If $i = 0xD800 Then $i = 0xE000
            $sChars &= ChrW($i)
        $sChars = StringRegExpReplace($sChars, StringReplace($sPattern, "[", "[^"), "")
    Local Static $iMax = StringLen($sChars)
    Local $sRand = ''
    For $i = 1 To $iLength
        $sRand &= StringMid($sChars, Random(1, $iMax, 1), 1)

It would be much more problematic to cope with the general case of a PCRE pattern.

Say you want to enforce a more complex set of rules, like any optionally signed non empty sequence of Unicode digits followed by a currency symbol (unlikely to be choosen for password): the pattern would have to be "(*UCP)(?=[-+]?d+pSc"

Then you'd have to dissect the pattern just like PCRE does at compile-time and filter allowed characters to build up a valid result.

This wonderful site allows debugging and testing regular expressions (many flavors available). An absolute must have in your bookmarks.
Another excellent RegExp tutorial. Don't forget downloading your copy of up-to-date pcretest.exe and pcregrep.exe here
RegExp tutorial: enough to get started
PCRE v8.33 regexp documentation latest available release and currently implemented in AutoIt beta.

SQLitespeed is another feature-rich premier SQLite manager (includes import/export). Well worth a try.
SQLite Expert (freeware Personal Edition or payware Pro version) is a very useful SQLite database manager.
An excellent eBook covering almost every aspect of SQLite3: a must-read for anyone doing serious work.
SQL tutorial (covers "generic" SQL, but most of it applies to SQLite as well)
A work-in-progress SQLite3 tutorial. Don't miss other LxyzTHW pages!
SQLite official website with full documentation (may be newer than the SQLite library that comes standard with AutoIt)

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Another solution for a class similar to the one defined in the first post. Although it's not a case sensitive nor a universal solution, I think the first step can possibly be a fairly efficient solution for sets containing between 11 and 16 characters. Some replacements can be made after generating the hex. I have not made any comparisons but it might still be of interest.


Local $sRandom = _RandomHexStr(Random(1, 1000, 1)), $sNewString = ""

; Add some underscores :)
For $i = 1 To StringLen($sRandom) +1
    While Not Random(0, 16, 1)
        $sNewString &= "_"
    $sNewString &= StringMid($sRandom, $i, 1)
ConsoleWrite($sNewString & @LF)

Func _RandomHexStr($iLen)
    Local $sHexString = ""
    For $i = 1 To Floor($iLen/7)
        $sHexString &= StringRight(Hex(Random(0, 0xFFFFFFF, 1)), 7)
    $sHexString &= StringRight(Hex(Random(0, 0xFFFFFFF, 1)), Mod($iLen, 7))
    Return $sHexString
EndFunc ;==> _RandomHexStr
Edited by czardas
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