How to generate a list of random numbers without duplicates in pure batch scripting?

Question

I want to generate a list of random numbers with a predefined number of items %RND_TOTAL% in the given range from %RND_MIN% to %RND_MAX%

Answer 1

I slightly modified a code I wrote some time ago:

@echo off
setlocal EnableDelayedExpansion

rem total number of random numbers:
set /A "RND_TOTAL=8"
rem range for random numbers (minimum, maximum):
set /A "RND_MIN=1, RND_MAX=10"

set /A "range=RND_MAX-RND_MIN+1"

rem Create an input list with all numbers in given range
set "input="
for /L %%i in (%RND_MIN%,1,%RND_MAX%) do (
   set "input=!input! %%i"
)
set "input=%input% "
echo  IN: [%input%]

rem Extract RND_TOTAL elements from input list in random order
set "output="
for /L %%i in (%RND_TOTAL%,-1,1) do (
   set /A "randIndex=(!random!*range)/32768+1, range-=1"
   call :MoveInputToOutput !randIndex!
)
echo OUT: [%output%]

goto :EOF

:MoveInputToOutput randIndex
for /F "tokens=%1" %%n in ("%input%") do (
   set output=%output% %%n
   set input=!input: %%n = !
)
exit /B

Output example:

> test
 IN: [ 1 2 3 4 5 6 7 8 9 10 ]
OUT: [ 8 7 9 3 1 4 5 2]

> test
 IN: [ 1 2 3 4 5 6 7 8 9 10 ]
OUT: [ 9 2 10 6 4 8 5 1]

> test
 IN: [ 1 2 3 4 5 6 7 8 9 10 ]
OUT: [ 1 2 4 3 8 5 7 9]

Excuse me, but I don't understand what %RND_INTER% value is used for...

EDIT: New version that use the %RND_INTER% value and have not limit in the number of random numbers generated.

@echo off
setlocal EnableDelayedExpansion

rem total number of random numbers:
set /A "RND_TOTAL=8"
rem range for random numbers (minimum, maximum, interval):
set /A "RND_MIN=1, RND_MAX=10, RND_INTER=1"

rem Create an input vector with all numbers in given range
set "n=0"
for /L %%i in (%RND_MIN%,%RND_INTER%,%RND_MAX%) do (
   set /A n+=1
   set "in[!n!]=%%i"
)
echo Input:
set in[
echo/

rem Extract RND_TOTAL elements from input vector in random order
for /L %%i in (1,1,%RND_TOTAL%) do (
   set /A "randIndex=(!random!*n)/32768+1"
   set /A "out[%%i]=in[!randIndex!], in[!randIndex!]=in[!n!], n-=1"
)
echo Output:
set out[