On Wed, 22 Nov 2017 17:11:53 +1100 Chris Angelico <ros...@gmail.com> wrote: > On Wed, Nov 22, 2017 at 3:55 PM, Greg Ewing <greg.ew...@canterbury.ac.nz> > wrote: > > Chris Angelico wrote: > >> > >> So the question is more: why, with Python being the way it is, do the > >> heap functions operate on a list? I think heapq.heapify is the answer: > >> in linear time, it heapifies a list *in place*. > > > > > > There's no reason a Heap object couldn't accomodate that > > case. E.g. the constructor could optionally accept an > > existing list to heapify and wrap. > > > > Yeah but if it's wrapping an existing list, it's not really > constructing a new object. Every other constructor in Python will make > something independent of its origin (if you call list() on a list, you > get back a brand new copy, for instance), but to take advantage of > in-place heapification, it would have to mutate the input. I think > that would be even more surprising.
In any case, copying a list a pretty cheap, so in-place heapification isn't a very important optimization. Regards Antoine. _______________________________________________ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/
