Using the average of a trend log value in a script

[dnavarro]

Thanks again for pointing me on the right direction, here is my code in case it's useful for someone else:

Code:

require('trends')
-- get data for today
dates = {}
dates['start'] = os.date('*t')
dates['end'] = os.date('*t')
dates['end'].day = dates['end'].day + 1

-- fetch values
today = trends.fetch('LUMINOSIDAD', dates)

-- initialize an array to store the rows
stored_data = {}

-- check if any data was returned
if today and #today > 0 then
  for i, row in ipairs(today) do
    -- store each row in the array
    if row ~=0 then -- Only when it has value, 0 means no value (future) 1 is the minimal value for the sensor.
      table.insert(stored_data, row)
    end
  end
else
  log('No data found for today')
end

-- get the last 6 items (30 min, reported every 5 min) and average them
local luminosidad_30_min = 0.0
local start_index = math.max(1, #stored_data - 5) -- ensure we don't go below index 1
for i = start_index, #stored_data do
  luminosidad_30_min = luminosidad_30_min + stored_data[i]
end

luminosidad_30_min = luminosidad_30_min/6