MissingItems

The MissingItems function is part of the HistoryFill class, and is used on those unusual cases where you are requesting data before the data point has any recorded information.

Because of this, not all drivers may choose to support the function and instead return empty results.

However, if you'd like to backfill data (taking the first sample and assuming it was the case all the way back in time), you can use this function to identify which channels had no data associated with them and call Backfill to fill in the blanks.

#After writing all data....
 
missing = history.MissingItems()
if len(missing) > 0:
   #Load the NEXT values for each of these missing points into the 'missingvalue' dictionary...
   for m in missing:
      history.Backfill(m,missingvalue[m])