2017-06-29 15:55 GMT+02:00 shubham goyal <skgoyal...@gmail.com>: > Thanks all > Great place to learn Python. > > On Jun 29, 2017 7:24 PM, "shubham goyal" <skgoyal...@gmail.com> wrote: > > Thankyou all. > > Great place to learn. > > On Jun 29, 2017 5:55 PM, "Mats Wichmann" <m...@wichmann.us> wrote: > > > On 06/29/2017 03:02 AM, Alan Gauld via Tutor wrote: > > > On 29/06/17 03:14, shubham goyal wrote: > > > > > >> This Question is asked in some exam. i am not able to figure it out. > > >> > > >> a = [0, 1, 2, 3] > > >> for a[-1] in a: > > >> print(a[-1]) > > >> > > >> its giving output 0 1 2 2 > > >> > > >> it should be 3 3 3 3 as a[-1] belongs to 3. > > >> can anyone help me figuring it out. > > > > > > This is quite subtle and it took me a few minutes to figure > > > it out myself. > > > > > > It might be clearer if we print all of 'a' instead > > > of a[-1]: > > > > > >>>> for a[-1] in a: > > > ... print(a) > > > ... > > > [0, 1, 2, 0] > > > [0, 1, 2, 1] > > > [0, 1, 2, 2] > > > [0, 1, 2, 2] > > > > > > What is happening is that a[-1] is being assigned the value > > > of each item in a in turn. The final iteration assigns a[-1] > > > to itself, thus we repeat the 2. > > > > > > Ugh. I guess on an exam where they're trying to see if you can tease it > > out, as you may one day have to debug such a sequence... but don't write > > code like that. One of the reasons people like "functional programming" > > is it avoids these kind of side effects. > > _______________________________________________ > > Tutor maillist - Tutor@python.org > > To unsubscribe or change subscription options: > > https://mail.python.org/mailman/listinfo/tutor > > > _______________________________________________ > Tutor maillist - Tutor@python.org > To unsubscribe or change subscription options: > https://mail.python.org/mailman/listinfo/tutor >
Hi All, just a comment ;-) Actually I do not know why it is good to ask similar things on a Python exam... Yes, I know that if one can answer these questions they show that they understand it. (Just a side question: Really understand? ;-) ) But a Pythonista never will write a code like this. I think this behaviour is just to "show" to the student that this is very strong school... :-( I think it would be better to teach how to write Pythonic code... BR, George _______________________________________________ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
