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

Next script first populates a temporary array with all numbers from target domain, then picks from it elements one by one at random positions into new array:

@echo off
setlocal    
setlocal enabledelayedexpansion

:: Populate array with all target numbers
for /L %%I in (%rnd_min%,1,%RND_max%) do (
        set /a idx="%%I"
        set "array[!idx!]=%%I
)

set /A I_NEED_SO_MANY_RANDOM_VALUES=%RND_max%-%rnd_min%
set /A TOTAL_UNUSED==%RND_max%-%rnd_min%

for /L %%I in (0,1,%I_NEED_SO_MANY_RANDOM_VALUES%) do (
    SET /A next_pick_index=!RANDOM! %% !TOTAL_UNUSED! 
    SET /A TOTAL_UNUSED-=1

    for /f "tokens=* delims= " %%a in ('echo !TOTAL_UNUSED!') do set unused_random=!array[%%a]!

    ::pick random value from initial array
    for /f "tokens=* delims= " %%a in ('echo !next_pick_index!') do set next_random=!array[%%a]!

    :: swap picked random value with the last not-used element in array
    SET "array[!next_pick_index!]=!unused_random!"

    :: put picked random value into new array
    SET "randomized_array[%%I]=!next_random!"
)

::output array to console
SET randomized_array[