Straightforward clear solution for The Longest Palindromic by Pouf - python coding challenges

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Straightforward solution in Clear category for The Longest Palindromic by Pouf

def longest_palindromic(text):
    s = len(text)
    for size in range(s)[::-1]:
        for index in range(s - size):
            word = text[index:index + size + 1]
            if word == word[::-1]:
                return word

March 2, 2016

Comments:

veky on March 3, 2016, 1:49 p.m.
If you're not worrying about performance, "slice twice" is a good tactic to avoid duplicating start index: <pre class='brush: python'>word = text[index:][:size+1] </pre> BTW, `reversed` builtin was added for a precise purpose of iterating in reverse. It would be nice to use it instead of [::-1]. <pre class='brush: python'>for size in reversed(range(n)): </pre>

Pouf on March 3, 2016, 11:58 p.m.
Golfing habits die hard :D You are right of course, reversed is way more clear. Thanks for the "slice twice" tip, I never thought of using it that way.

veky on March 4, 2016, 5:40 a.m.
<blockquote> Golfing habits die hard :D </blockquote> Yes, that's one of my (few) regrets here on CiO... it seems I haven't stressed enough the point that you first have to have a firm grasp on Pythonic, readable, beautiful code, so you can then golf. Too many people have been seduced into golfing without first speaking Python as G-d (Guido, of course:)) intended them to. :-) Slice twice is a natural consequence of Guido being seduced by Dijkstra and his very convincing arguments for index intervals. Dijkstra's notation is indubitably useful sometimes, but about an equal number of times (or slightly more often) we don't need "start til stop", but "start plus len". Of course, the point was that you can always convert one to the other via "slice twice", while conversion in another direction requires computing a difference. But Dijkstra was a mathematician, and minimizing the number of required operations was more important thing than performance. For programmers, `int.sub` is much more efficient than another slice, but the notation has stayed. Ghosts of tradition. :-)

Pouf on March 4, 2016, 1:43 p.m.
<blockquote> Too many people have been seduced into golfing without first speaking Python as G-d (Guido, of course:)) intended them to. :-) </blockquote> Fortunately, Clear is the default category and people are still distributing most of the points there. As long as we have you reminding us about reversed(list), there is still hope ! Thank you for the insight. I can't imagine the number of tough choices you have to make when designing a language...

veky on March 4, 2016, 2:54 p.m.
<blockquote> I can’t imagine the number of tough choices you have to make when designing a language… </blockquote> If you read all my posts here (which would take about a year I suppose:)), you'll learn many of them. :-)

Pouf on March 4, 2016, 4:08 p.m.
I usually do, I'm a big fan ;)

oduvan on Jan. 25, 2017, 10:18 a.m.
a video code review from @veky <a href="https://www.youtube.com/watch?v=bAea_X5cCJo">https://www.youtube.com/watch?v=bAea_X5cCJo</a>

bsquare on Sept. 2, 2019, 9 a.m.
@veky I didn't know you were a speaker too ^^

veky on Sept. 2, 2019, 9:15 a.m.
As I said, you don't know a lot about me. :-D

bsquare on Sept. 2, 2019, 9:17 a.m.
Of course, if you keep your little secrets ...

veky on Sept. 2, 2019, 9:18 a.m.
I don't. It's simply too much. :-)

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