random numbers without repeating

[Rapide]

How to generate single digit numbers without repeating? I have wrote this much so far :

$min=1

$max=9

 $result = Consolewrite(Random($min,$max,1))

$temp = $result 

I do not know what to do next. To be more specific, the numbers should repeat, but should not repeat (same number) one after the other. The new result (number) should always be not equal to previous result.

Example:

1 2 9 9 ❌

1 9 2 9 ✔️

Thank you^^

 

 

[TheXman]

Here's one of many ways that it could be done.

Example()
Func Example()
    Const $kNUMBER_OF_DIGITS = 6

    Local $iRandomDigit = 0
    Local $sDigits = ""

    While StringLen($sDigits) < $kNUMBER_OF_DIGITS
        $iRandomDigit = Random(0, 9, 1)
        If StringRight($sDigits, 1) <> $iRandomDigit Then $sDigits &= String($iRandomDigit)
    WEnd

    ConsoleWrite(StringFormat("%s random digits: %s", $kNUMBER_OF_DIGITS, $sDigits) & @CRLF)
EndFunc

 

[iamtheky]

pretty much the same thing in a For loop instead of a while loop.  Could probably also use a Do loop in a similar manner to the solution above if you wanted the practice.

$min=1
$max=9
local $last , $out
$EndStringLength = 5

For $i = 1 to $EndStringLength

$n = Random($min,$max,1)
    If $n=$last Then
       $i -= 1
       ContinueLoop
    EndIf
$out &= $n
$last = $n

Next

msgbox(0, '' , $out)

 

[IAMK]

$min = 1
$max = 9
$prev = 0
$curr = Random($min, $max, 1)

While(1)
    $curr = Random($min, $max, 1)
    
    If($curr <> $prev) Then
        ConsoleWrite($curr & " ")
        $prev = $curr
    EndIf
WEnd

Simplest, but I suggest you edit it.

[jchd]

That isn't a pseudo-random sequence then.

[IAMK]

@jchd It still is, just with 1 more condition.

[mikell]

Something a bit simpler  

$prev = '0'
Msgbox(0,"",  Execute(StringRegExpReplace('aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa', '(a)', _ 
    "(Assign('s', StringReplace('123456789', $prev, '')) * Assign('a', StringSplit($s, '')[Random(1, StringLen($s), 1)]) * (Assign('prev', $a)) * $a) & ") & "''") )

 

[Melba23]

Rapide,

Just use _ArrayShuffle:

#include <Array.au3>

Global $aArray[9]

For $i = 0 To 8
    $aArray[$i] = $i + 1
Next

_ArrayDisplay($aArray, "Loaded", Default, 8)

_ArrayShuffle($aArray)

_ArrayDisplay($aArray, "Shuffled", Default, 8)

The well-known algorithm used for shuffling is as good as you can get.

M23

[mikell]

Melba,
Your code doesn't allow 2 or more same digits in the final number 

[Melba23]

mikell,

True, I only read the first line of the post ("How to generate single digit numbers without repeating") and not the completely different requirement stated later ("To be more specific, the numbers should repeat, but should not repeat (same number) one after the other").

M23

[jchd]

1 hour ago, IAMK said:

It still is, just with 1 more condition.

Hence it isn't a pseudo-random sequence!

[mikell]

@jchd

Just joking with trying this one-liner. But is this correct ?

Msgbox(0,"",  Execute(StringRegExpReplace('aaaa', '(^|a)', _ 
    "('$1'=='' ? Eval(Assign('prev', '0')) : (Assign('s', StringReplace('123456789', Eval('prev'), '')) * Assign('a', StringSplit(Eval('s'), '')[Random(1, StringLen(Eval('s')) ,1)]) * Assign('prev', Eval('a'), 'mikell was here') * Eval('a'))) & ") & "''") )

 

[junkew]

so 1 9 1 9 1 9 1 9 1 9 1 9 1 9 1 9 ✔️ or is there a broader requirement regarding distribution of the digits you want?

 

 

[IAMK]

@jchd Correct me if I'm wrong, but it's pseudo-random, because it's not entirely random. The reason it's not random is because it has conditions; The usual ones being a key (usually time and date) and a formula. Hence, adding more conditions while still containing some "random" factor would still make it pseudo-random.

[Gianni]

... my 2 cents

Local $min = 1, $max = 9

For $i = 1 To 40
    ConsoleWrite(_RandomMod($min, $max) & " ")
Next
ConsoleWrite(@CRLF)

Func _RandomMod($min, $max)
    Local Static $iNotOnNextRnd = Random($min, $max, 1)
    $iNotOnNextRnd = Mod(Random($iNotOnNextRnd + 1, $iNotOnNextRnd + ($max - $min), 1), $max + 1)
    $iNotOnNextRnd += ($min * ($iNotOnNextRnd < $min))
    Return $iNotOnNextRnd
EndFunc   ;==>_RandomMod

 

Edited December 3, 2018 by Chimp
changed var name

[iamtheky]

I liked the array idea too, it seems useful if you ever needed to manipulate the original set

#include<array.au3>
local $rnd=[0,1,2,3,4,5,6,7,8,9]
$old = -1
$out = ""
$length = 7

For $i = 1 to $length
  _ArrayShuffle($rnd)
  $pop = _ArrayPop($rnd)
    If $old > -1 Then _ArrayAdd($rnd , $old)
  $old = $pop
  $out &= $pop
Next

msgbox(0,'', $out)

 

Edited December 3, 2018 by iamtheky

[jchd]

1 hour ago, IAMK said:

Correct me if I'm wrong, but it's pseudo-random, because it's not entirely random. The reason it's not random is because it has conditions; The usual ones being a key (usually time and date) and a formula. Hence, adding more conditions while still containing some "random" factor would still make it pseudo-random.

This isn't the semantic of "pseudo-random" one can find in any mathematical source I know of. The term "pseudo-" is to be understood as opposed to "naturally-". For instance true random generators may be based on some radioelement decay, something which is physically proven random. Careful sampling of genuine white noise can be another "natural" source.

In IT, "pseudo" refers to an algorithmic source, for instance the one used by AutoIt Random() function, because general-purpose computers have long been driven by determinism, something difficult to use to mimic the random characteristic of some physical phenomenoms.

Uncommon requirements like those of the OP could possibly be coined "non-stuttering-biased pseudo random". Resulting sequences are an infinitely small subset of all truly random sequences build from the same digits set.

[RTFC]

See RdRand for an approach that samples on-chip thermal noise, smilar to what @jchd suggested.

.

[jchd]

Random is pretty good at the simple distribution test:

; 100,000 non-repeating digits
Local $s
For $i = 1 To 100000
    $s &= _NextRndDigit()
Next
; ConsoleWrite($s & @LF)        ; yes that's a loong string, just for checking the distribution below
Local $aDigits = StringSplit($s, "", 2)
_ArraySort($aDigits)
Local $s = _ArrayToString($aDigits, "")
Local $aHisto[9]
For $i = 0 To 8
    $aHisto[$i] = StringLen(StringRegExp($s, ($i + 1) & "+", 1)[0])
Next
_ArrayDisplay($aHisto)

Func _NextRndDigit()
    Static $aDigits = [1, 2, 3, 4, 5, 6, 7, 8, 9], $iStart = 0
    Local $iIndex = Random($iStart, 8, 1)
    $iStart = 1
    Local $iDigit = $aDigits[$iIndex]
    Local $iOld = $aDigits[0]
    $aDigits[0] = $iDigit
    $aDigits[$iIndex] = $iOld
    Return $iDigit
EndFunc