Reposting to list, instead of directly to kjs On 09/08/2014 08:45 PM, kjs wrote: > Thanks for the consideration Michael. If you do get the data, and are > able to run the code, let me know if you notice anything interesting.
Yeah I don't think I'll be able to have the time to download a 3 GB file. >> Is there a reason you are using setattr and getattr instead of a proper >> data structure? both of those calls are rather expensive. Would >> probably be cheaper to use some kind of array, dictionary, or other >> purpose-built data structure? >> > > You're right, a dictionary can do everything I need and more. This > happened to be the first thing I thought of, and I didn't imagine it > would be very expensive. I figured it was simply a different way of > defining and retrieving a class variable. IE setattr(self, foo, True) == > self.foo = True. Yes you're correct. It is the equivalent. But it always involves lookup in the object's dictionary, which is big O order O(n log n) complexity for each and every access. A list would be far faster, essentially O(1) (I think?) after the single name lookup, since you can access the elements by number. Indexing into a list doesn't involve doing name lookups; you just specify an offset. No idea how much faster, but significantly so. If a list is too slow, there are other array-like classes you can use (like numpy arrays) that do offer true O(1) lookups. Besides that, it's not typical use of setattr and getattr in python. -- https://mail.python.org/mailman/listinfo/python-list
