Re: Help with sets

On 10/5/2010 3:01 AM, Ian Kelly wrote:

self._pos = {predicate: {object: {subject: None}}}

That's a bit ugly because the None serves no purpose here; the value
associated with the subject has no meaning in this context.

This is what we did in Python before sets were added.

> It also
uselessly takes up space in memory that could add up to significant
wastage if the data structure grows to be large.

The other major difference between dicts and sets is that sets provide
mathematical operations such as intersection and difference that dicts
do not, but that doesn't appear to be relevant in this context.

These two reasons are why we added sets.

Terry Jan Reedy