Search code examples
luashufflerandom

How do you do the Fisher-Yates shuffle in Lua

I've been asking questions on random numbers, and I decide the Fisher-Yates shuffle would be the best option. I make a table 't'

t = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}

Now, how would I even shuffle these and be able to use them individually, for example generate the results in another table u

u = {}
Solution

  • NOTE: Check the other answer https://stackoverflow.com/a/68486276/1190388 which fixes an issue in the code snippet below as well as providing other alternatives

    If you do not have holes in your table:

    math.randomseed(os.time()) -- so that the results are always different
function FYShuffle( tInput )
    local tReturn = {}
    for i = #tInput, 1, -1 do
        local j = math.random(i)
        tInput[i], tInput[j] = tInput[j], tInput[i]
        table.insert(tReturn, tInput[i])
    end
    return tReturn
end