Question

I need a data structure which can handle the following:

date_from (datetime)
date_to (datetime)
value (float)

…and I need to be able to ‘query’ this data structure based on a datetime (e.g. in pseudocode: SELECT * FROM data_structure WHERE a_datetime >= date_from AND a_datetime <= date_to;).

If there isn’t a result from this ‘query’, I would need to be able to insert a new value into the data structure.

What’s the best way of doing this? (I’m a bit stuck at the moment)

Answer 1

Have a look at this SortedCollection Recipe. It uses the bisect module and lets you created a keyed collection. E.g.:

>>> from SortedCollection import SortedCollection
>>> from operator import itemgetter
>>> s = SortedCollection(key=itemgetter(0))
>>> s.insert((1,2,'a'))
>>> s.insert((10,20,'b'))
>>> s.insert((20,30,'c'))
>>> s.find_le(10)
(10, 20, 'b')

May help you create your cache of time period information, the bisect approach should let you access your date-keyed information efficiently.