>>>>> Soni L. writes: > Steven d'Aprano writes: > > range(1000, 1000000) > > (x for x in range(1000, 1000000)) # waste of time and effort
> Actually, those have different semantics! That's not real important. As Stefan Behnel points out, it's simple (and efficient) to get iterator semantics by using iter(). The big issue here is that Python is not the kind of declarative language where (x for x in int if 1_000 ≤ x ≤ 1_000_000)[1] is natural to write, let alone easy to implement efficiently. Aside from the problem of (x for x in float if 1_000 ≤ x ≤ 1_000_000) (where the answer is "just don't do that"), I can't think of any unbounded collections in Python that aren't iterables, except some types. That makes Steven's criticism pretty compelling. If you need to design a collection's __iter__ specially to allow it to decide whether the subset that satisfies some condition is exhausted, why not just subclass some appropriate existing collection with a more appropriate __iter__? Footnotes: [1] See what I did there? ;-) _______________________________________________ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/
