CC nixie fluid readout

print("Printing tank fullness to nixie tubes")
local prevTankPercent = -1  -- the tank doesn't seem to show up when no updates are given
local blinkFlag = false
while true do
    local tank = peripheral.find("modern_industrialization:large_tank_hatch")
    local display = peripheral.find("create_source")

    local percentage = -1
    local tanks = tank.tanks()

    if #tanks > 0 or tanks[1] ~= nil then
        local amount = tanks[1].amount
        local capacity = tanks[1].capacity
        local ratio = amount / capacity
        percentage = ratio *100

        print(tostring(os.time()).."new data")
    else
        print(tostring(os.time()) .. "outdated info")
        percentage = prevTankPercent
    end

    local outstr = ""


    if percentage == -1 then
        outstr = outstr .. " ??.??%"

        print(tostring(os.time()) .. "no data")
    elseif percentage == 1 then
        outstr = outstr .. "100.00%" .. " "
    else
        local dig_0 = math.floor((percentage / 10) % 10)
        local dig_1 = math.floor(percentage % 10)
        local dig_2 = math.floor((percentage *10) %10)
        local dig_3 = math.floor((percentage *100) %10)

        outstr = outstr .. " " .. tostring(dig_0) .. tostring(dig_1) .. "." .. tostring(dig_2) .. tostring(dig_3) .. "%" .. " "
    end

    if blinkFlag == true then
        if (percentage > prevTankPercent) then
            outstr = outstr .. "^"
        elseif (percentage < prevTankPercent) then
            outstr = outstr .. "v"
        else
            outstr = outstr .. " "
        end
    end

    display.clear()
    display.setCursorPos(1,1)
    display.write(outstr)

    prevTankPercent = percentage
    blinkFlag = not blinkFlag
    sleep(1)
end