On Thu, Aug 10, 2017 at 8:28 AM, Steve D'Aprano <steve+pyt...@pearwood.info> wrote: > Every few years, the following syntax comes up for discussion, with some > people > saying it isn't obvious what it would do, and others disagreeing and saying > that it is obvious. So I thought I'd do an informal survey. > > What would you expect this syntax to return? > > [x + 1 for x in (0, 1, 2, 999, 3, 4) while x < 5]
I would expect the for to be an outer loop and the while to be an inner, so this would loop infinitely. > For comparison, what would you expect this to return? (Without actually trying > it, thank you.) > > [x + 1 for x in (0, 1, 2, 999, 3, 4) if x < 5] This is already valid syntax. I would expect [1, 2, 3, 4, 5]. > [x + y for x in (0, 1, 2, 999, 3, 4) while x < 5 for y in (100, 200)] Infinite loop. > [x + y for x in (0, 1, 2, 999, 3, 4) if x < 5 for y in (100, 200)] [100, 200, 101, 201, 102, 202, 103, 203, 104, 204] -- https://mail.python.org/mailman/listinfo/python-list
