Factorio Sum Resources

/c surface = game.player.surface;
counts = {};
for _, ore in pairs(surface.find_entities_filtered({type="resource"})) do
    if counts[ore.name] == nil then
      counts[ore.name] = 0;
    end
    counts[ore.name] = counts[ore.name] + ore.amount
end
for name, cnt in pairs(counts) do

  len = string.len (string.match (cnt, "%d+"));
  if (len >= 1) and (len <= 3) then
    divideBy = 1
  elseif (len >= 4) and (len <= 6) then
    divideBy = 1E3
    numberSize = "K"
  elseif (len >= 7) and (len <= 9) then
    divideBy = 1E6
    numberSize = "M"
  elseif (len >= 10) and (len <= 12) then
    divideBy = 1E9
    numberSize = "B"
  elseif (len >= 13) and (len <= 15) then
    divideBy = 1E12
    numberSize = "T"
  else
    return "number error: " .. str
  end
  str = string.gsub(string.format("%.1f", tonumber(cnt)/divideBy), "%.0", "") .. numberSize;
  game.player.print(surface.name..": ")
  game.player.print(name..": "..str)
end