Cheat Engine - dropdown list string to bytes

-- Cheat Engine Lua script snippet
-- formats string drop down list values to AoBs and writes 0s to unused bytes
for i = 0, AddressList.count - 1 do
  local mr = AddressList[i]

  -- identify memory records to change
  if mr.Type == vtString
     and not mr.IsGroupHeader
     and mr.DropDownCount > 0
     and not mr.DropDownLinked then    -- possibly undesirable; I haven't experimented w/ linking

    local size = mr.String.Size
    -- sanity check
    for j = 0, mr.DropDownCount - 1 do
      assert(#mr.DropDownValue[j] <= size,
             ('Error: memory record "%s" (#%d, ID %d): drop down value "%s" longer than size "%d".'):format(
             mr.Description, i, mr.ID, mr.DropDownValue[j], size))
    end

    mr.Type = vtByteArray
    mr.Aob.Size = size

    mr.DropDownList.beginUpdate()
    for j = 0, mr.DropDownCount - 1 do
      local val_str = mr.DropDownValue[j]
      local bt = stringToByteTable(val_str)
      for k = #val_str + 1, size, 1 do
        bt[#bt+1] = 0
      end
      if bt[#bt] ~= 0 then
        print(('Warning: memory record "%s" (#%d, ID %d): value of drop down description "%s" has no null terminator.'):format(
             mr.Description, i, mr.ID, mr.DropDownDescription[j]))
      end
      for k,v in ipairs(bt) do
        bt[k] = ('%02X'):format(v)
      end
      mr.DropDownList.setString(j, ('%s:%s'):format(table.concat(bt), mr.DropDownDescription[j]))
    end
    mr.DropDownList.endUpdate()
  end
end