On Saturday, June 4, 2016 at 11:37:18 PM UTC+12, Ned Batchelder wrote: > On Friday, June 3, 2016 at 11:43:33 PM UTC-4, Lawrence D’Oliveiro wrote: > > On Saturday, June 4, 2016 at 3:00:36 PM UTC+12, Steven D'Aprano wrote: > > > You can exit a loop because you have run out of items to process, or you > > > can > > > exit the loop because a certain condition has been met. > > > > But why should they be expressed differently? > > > > item_iter = iter(items) > > while True : > > item = next(item_iter, None) > > if item == None : > > break > > if is_what_i_want(item) : > > break > > #end while > > Do you actually write loops like this?
Is that a non-trolling question? Yes. All the time. > If this appeared in a code review, first we'd have a conversation about > what this code was meant to do ... I would hope not. > ...and then I would ask, "Why aren't you using a for loop?" ... and then I would ask, “Didn’t you read my previous postings where I pointed out the issues with them?” Here <https://en.wikibooks.org/wiki/Python_Programming/Databases> is another example: see the section “Looping on Field Breaks”. A while-True scales gracefully to complex situations like that. I much prefer universal, adaptable constructs, rather than having to remember different solutions for special cases. > I suspect most Python programmers would be similarly confused about > why you aren't using one of the central constructs of the language. When a language has good and bad parts, it behooves the wise programmer to concentrate on the good parts and try to ignore the bad. Python’s for-loops have their uses—I *did* point this out too, did you not notice?—but they are best confined to the situations that they are good at. > What's next? "Why have both if and while? A goto will work for both!" Passive-aggression aside, funny you should mention that. I use a goto-free structured-programming style in my C code, as exemplified here <https://github.com/ldo/dvd_menu_animator/blob/master/spuhelper.c>. I find it reduces problems with forgetting to free memory, or freeing it twice. -- https://mail.python.org/mailman/listinfo/python-list
