Question

I have a default dict of dicts whose primary key is a timestamp in the string form ‘YYYYMMDD HH:MM:SS.’ The keys are entered sequentially. How do I access the last entered key or the key with the latest timestamp?

Answer 1

Use an OrderedDict from the collections module if you simply need to access the last item entered. If, however, you need to maintain continuous sorting, you need to use a different data structure entirely, or at least an auxiliary one for the purposes of indexing.

Edit: I would add that, if accessing the final element is an operation that you have to do very rarely, it may be sufficient simply to sort the dict’s keys and select the maximum. If you have to do this frequently, however, repeatedly sorting would become prohibitively expensive. Depending on how your code works, the simplest approach would probably be to simply maintain a single variable that, at any given point, contains the last key added and/or the maximum value added (i.e., is updated with each subsequent addition to the dict). If you want to maintain a record of additions that extends beyond just the last item, however, and don’t require continuous sorting, an OrderedDict is ideal.