On Sun, 7 Aug 2016 08:05 am, Lawrence D’Oliveiro wrote:
> On Saturday, August 6, 2016 at 12:08:30 PM UTC+12, bream...@gmail.com
> wrote:
>> A couple or three years old but this is well worth seeing for anybody,
>> regardless of your Python expertise.
>> http://nedbatchelder.com/text/iter.html
>
> A loop like
>
> for i in ... :
> ...
> if ... cond ... :
> break
> ...
> #end for
>
> actually has two different ways to terminate. Is there any good reason for
> them to be written two different ways?
Yes. The two ways of ending the loop are distinct and different:
- reach the end, and stop;
- bail out early.
When you read a book, there are two ways of stopping:
- reach the end, and run out of pages to read, so you stop;
- give up reading early, and just put the book away.
(Or possibly throw the book across the room.)
Why would you treat these two cases in the same way?
interested = True
for page in book:
if interested:
read(page)
if bored_now():
interested = False
finished = False
while not finished:
try:
page = next(book)
except StopIteration:
finished = True
else:
read(page)
if bored_now():
finished = True
--
Steve
“Cheer up,” they said, “things could be worse.” So I cheered up, and sure
enough, things got worse.
--
https://mail.python.org/mailman/listinfo/python-list
