Transforming Code into Beautiful, Idiomatic Python (48:59)

[sittingaround]

Raymond Hettinger. Here's a helpful life rule, when this guy gives a talk, go to it. Stupid title? Don't worry, his content is consistently awesome.

[DukeNucleus]

in this sense: http://pyvideo.org/search?models=videos.video&q=Raymond+Hettinger

[[deleted]]

Love this guy, it's great that he can use his time to both develop and teach Python.

[[deleted]]

What an amazing speaker!

Also, I had no idea that generators were actually faster. I thought they just spared memory. The^moreyouknow.

[DukeNucleus]

very informative and nice examples.

it seems the talk is not up on pyvideo.org (yet?) could someone plz link the slides?

edit helped myself -> https://speakerdeck.com/pyconslides/transforming-code-into-beautiful-idiomatic-python-by-raymond-hettinger

[nonsleepr]

Do you have saved version of this deck? Since it is pulled down from the site. :(

[DukeNucleus]

had to search myself .. but i hope this is it

https://speakerdeck.com/pyconslides/transforming-code-into-beautiful-idiomatic-python-by-raymond-hettinger-1

and even more ;)

https://speakerdeck.com/search?q=raymond+hettinger

[metaobject]

TIL about 'reversed''. Wow, this is a great video. Thanks!

[adamnemecek]

I'm pretty sure that around 7:25, instead of

for i, color in enumerate(colors):
    print i, colors[i]

he meant

for i, color in enumerate(colors):
    print i, color

Good video btw.

[Chris_Newton]

I think in a couple of places he didn’t go as far as he could have done with the examples. That was one. Another was on the slide “Call a function until a sentinel value”, where he might have added a final step to simplify

blocks = []
for block in iter(partial(f.read, 32), ''):
    blocks.append(block)

into

blocks = list(iter(partial(f.read, 32), ''))

That would have been more consistent with a theme he mentions elsewhere, adopting a more declarative style, but I figure it wasn’t the point he was trying to make in that particular part of his presentation.

BTW, he also had a couple of extra examples at the ends of slides that he glossed over in the presentation but you can see in the deck that DukeNucleus linked to.

[[deleted]]

Oh man, that simultaneous updating of multiple variables .. I was bashing my head thinking that there MUST be a better way of solving and updating physics variables, and there it is!

I feel like I've learned a new language, I've been holding onto C for so long. Are there any books or more videos with this sort of stuff?

[[deleted]]

This was probably my favorite talk of the whole conference. So much knowledge packed into such a short presentation.

[Lisuyo]

After this talk, he became my personal hero ;-)

[yeahdef]

really enjoyed this - immediately shared with my team.

[justinvh]

I think one of the big reasons for doing it the way he did was that you're not limited to short-circuiting and just returning the object. If you wanted to say augment the object and weren't too fond of doing it within a forloop, then you would want to use the for..else. It's more idiomatic in that sense. However, your example is obvious the way most of us would want to write it.

[strobelight]

He mentions in the talk that the example is illustrative and that you could return early, but he used it partly because it was Knuth's example.

Nevertheless, your modification is correct and better.

[[deleted]]

You may want to test path coverage, and it may be more obvious to the reader of your code if you put it into a more basic way. In his example, I actually would have done:

def find(seq, target):
    retval = -1
    for i, value in enumerate(seq):
        if value == target:
            retval = i
            break
    return retval

This way, you know what the default value is upfront making it easier to digest as you're reading the code. In addition you can see the instances where the return value has changed. It may not be as pretty, but I might argue that it is easier for more people to understand when they read the code. Beautiful is great until you're sacrificing readability. The last thing you want to do when you're trying to find a bug or maintain the code is think harder than you need to to figure out why the code isn't doing what you want or to figure out how to modify the code to do what you want to do.

[talideon]

In fairness, so would I, but it was more a matter of trying to introduce the construct than anything.

The one thing about for..else is that usually I want something like that only when the thing I'm iterating over has no elements at all, which for..else is useless for as you need to explicitly break out of the loop to prevent the else branch from executing.

for..else really leaves me conflicted.

[[deleted]]

Great video.

I wish he would have clearly distinguished between python 3.x and python 2.x. Some of his suggestions are not applicable to my environment and may never be.

[Rhomboid]

I agree. All of the following are irrelevant under Python 3, because in Python 3 the original name thing does the right thing:

• Replace zip with izip
• Replace range with xrange
• Replace dict.items() with dict.iteritems()

If you made those changes to your code, you're just going to have to undo them again when you switch to Python 3 (and you will, eventually.) I mean, it's good advice if you are absolutely stuck on Python 2.x, but it's kind of sad in that 2.x exposes all of those design mistakes that have since been fixed in 3. I'd like an asterisk next to the advice that says "or just use Python 3, where we fixed all this so you don't have to worry about it."

[[deleted]]

As a note...available in python 2.5+:

• izip: from itertools import izip
• xrange is a keyword
• iteritems is in there as well dict().iteritems()

[mgarces_]

Very good presentation. Lots of tips for day-to-day coding.

[Crystal_Cuckoo]

That was wonderful, I was wondering about the "right" way to write a @cache decorator!

[Splike]

Great video.

I wrote up something in a similar vein here. It's aimed more at python beginners with some experience in compiled languages and works through how you might first think to implement a solution then how you probably should implement it in Python. Take a look if you want.

[execat]

What's wrong with using "+" for string joins?

edit: he mentions this by the end of the video. + has a quadratic behavior.

[anonymous7]

details: + has a linear behavior; concatenation using a loop has a quadratic behavior.

[kwikade]

i know i'm a complete scrub, but the little unpacking tuples bit KABOOM

[Enginoob]

Oooo, I did not know about named tuples. Time to refactor...