How to shuffle the letters of a word using lua

Question

I used this str_shuffle() function in PHP and meka this api I need to do the same idea shuffle the letters With space between them but with lua to working with telegram bots I searched a lot and found nothing similar

Answer 1

Here is some code that does what you want with comments to explain how it works:

function tablelength(table) -- to calculate the length of a table
  local count = 0
  for _ in pairs(table) do count = count + 1 end -- loop through each of its items and add to a counter
  return count
end

function stringtoletters(text) -- split a string into its individual characters
  local letters = {}
  for a = 1, string.len(text) do -- loop through each character in the string and add it to the table
    table.insert(letters, string.sub(text, a, a))
  end
  return letters
end

function randomlyreorganizetext(text) -- the function that actually does the stuff AKA the meat
  local letters = stringtoletters(text)
  local n = tablelength(letters)

  math.randomseed(os.time()) -- initialize the random number generator
  math.random(); math.random(); math.random() -- the first few numbers are apparently not very random so get rid of them

  for i=n,1,-1 do -- go through each character and switch it out with another one of the of the characters at random
    local j = math.floor(math.random() * (i-1)) + 1 -- decide which character to swap with
    local tmp = letters[i] -- make a backup of the current value
    letters[i] = letters[j] -- change to random characters value
    letters[j] = tmp -- put what used to be the current value into the random characters position
  end

  return table.concat(letters, " ") -- turn the table back into a string and put spaces between each element
end

print(randomlyreorganizetext("hello"))

Answer 2

math.randomseed(os.time())

local function shuffle(str)
   local letters = {}
   for letter in str:gmatch'.[\128-\191]*' do
      table.insert(letters, {letter = letter, rnd = math.random()})
   end
   table.sort(letters, function(a, b) return a.rnd < b.rnd end)
   for i, v in ipairs(letters) do letters[i] = v.letter end
   return table.concat(letters)
end

print(shuffle("How to shuffle the whole UTF-8 string"))

Answer 3

Here is my take. The first gsub indexes the letters in the string in the order they appear in it. Then we shuffle the indices and use the shuffled indices to remap the letters with another gsub.

s="How to shuffle the letters of a word using lua"
t={}
n=0

s:gsub("%a",function (c)
        if t[c]==nil then
            n=n+1
            t[n]=c
            t[c]=n
        end
    end)

math.randomseed(os.time())
for i=n,2,-1 do
    local j=math.random(i)
    t[i],t[j]=t[j],t[i]
end

z=s:gsub("%a",function (c) return t[t[c]] end)
print(s)
print(z)