Note to Python 3 Users: - izip is just zip - d.iteritems() is just d.items() - To use defaultdict: You have to do the following --> from collections import defaultdict

Man YT recommended it after 8 yrs In search of gold I found diamond

"If you are mutating something while you are iterating over it, you are living in a state of sin and you deserve whatever happens to you" :D loled so hard on this one! 20:20

10:20 Beautiful syntax highlighting

I’ve been using Python for over a decade (informally trained) and haven’t learned so many great tidbits so quickly in a long time. Awesome talk!

This guy is seriously amazing, love his style of teaching

"There's two kinds of people in the world: people who've mastered dictionaries and total goobers." - Raymond Hettinger

6 years old but still good advice. Raymond is a great teacher.

The ignored() idiom exists in Python 3.4+ but is called suppress(): # NEW WAY in Python 3.4+: from contextlib import suppress with suppress(OSError): os.remove('foo.txt')

At 44:00, The `with ignored(OSError)` has been renamed to `with suppress(OSError)` and is from the contextlib package.

10 years old video, and it is gold.

Amazing talk ! Probably best I've heard in all 26 year I'm coding. A handful of smiles and headful of HQ knowledge. Thank you, Raymond !

This video was the video that got me interested in writing ideomatic Python and iterators. I've revisited it now and then ever since 1. year at uni. Amazing lecturer.

This is a must see video for an python developer. Fantastic!

Dude’s kind of a colossal badass. Not even mad at the Casey Kasem vibe at all. He’s a beast.

Love this guy. I was quite disappointed when it ended. I was so expecting a much much longer video :D

This dude is off the hook smart.

This man is technically brilliant and hilarious. Not something you see everyday. Thanks for the nice speech!!

Found this to be one of the most useful python talks thus yet on youtube.

This presentation is simply awesome !! hands down !!

This is probably the best presented programming video I've ever seen. Thanks!

I thoroughly enjoyed your presentation! Take the old-fashioned, ugly, slow way of doing things and instead do the new-fangled, beautiful, fast way. I love it!

I literally just watched this a second time for the entertainment value! Raymond Hettinger is hilarious! Not only was watching this a lot of fun, but super-informative and efficient. I'm going to go check out some of his other talks. If I'm gonna learn python, it might as well be from this dude!

Where have I been All this time only to find this GEM right now ??? This video is very great and a MUST WATCH for any pythonista

I can listen to Mr Hettinger all the time!!! Thanks for the presentation and your contributions.

Thank you so much for this wonderful lecture. I think this insight might be helpful . As a Novice programer I had a few issues understanding how some of core functions in Python worked and what was because the people who taught me where using derived language examples. Phrases like "if you've code an another language....". But I haven't well time passed I learned the hard way later got to this video and inevitably think that things would been a lot easier for me if this lecture was around.

Just one video and learned more things worth years... great tips!

Very nice. In just 50 minutes I learned moe then in the last month.

at 7:22 it should not for i, color in enumerate(colors): print i,'--->',color[i] but for i, color in enumerate(colors): print i,'--->',color may be printing mistake

What amazing techniques! Why I haven't seen this sooner. Thank you a lots

Really insightful video. Didn't even notice the time fly by. Already feel better as a Python programmer.

That talk was amazing. Will need to watch this video a few times.

Raymond's an entertaining, engaging presenter. Good mix of material here, definitely came away richer for the experience.

First - this is an awesome piece, I didn't knew Raymond Hettinger was to be blamed for so many iterators in python, and I truthfully love this guy now that I know what he did for most of my days! :) There is a small bug in 15:58 onwards due to the missing tgt variable, but the more important thing is that it can get even more beautiful (IMHO) from: def find(seq, target): for i, value in enumerate(seq): if value == target: break else: return -1 return i to this: def find(seq, target): for i, value in enumerate(seq): if value == target: return i return -1 not that the for/else is not nice in some other cases, this was probably just not the right example for it.

Thank you for the lecture, sir. I appreciate the review of some critical "dos and don'ts" for beginners.

"Start open source contributions to project by going in and placing doc strings". This is a brilliant idea! I've wanted to start contributing for so long but didn't feel I have the skills, I'm gonna do this!!!

Amazing stuff! Love the functional style entering Python

this may be the best python video I've seen online

This is priceless! Thanks for the upload.

I wish this guy was my teacher

Initially I refuse to believe any developer wouldn’t know what “in” semantically means, but then I’m reminded of all the code I’ve seen.

In python you make your video with audience, clapping, laughing and commenting. Python is fantastic.

Thanks a lot for this video. Raymond is an awesome guy.

probably best python video ive ever seen

Documented version gist.github.com/JeffPaine/6213790

Love Raymond's presentation style.

I m watching 7 years old video and leaning lots of amazing things.... :-) you are really great.

I learned a LOT with this video, Kudos Raymond Hettinger 15:52 for/else, I've always wanted this. For a long time now, I've replicated this behavior in Java enclosing the for inside try/catch and throwing a custom exception of the kind 'BrokenLoop', which looks waaay better, despite feeling forced and inappropriate. Huge like.

Man, this is awesome.

Wow - amazing talk - informative, concise, immediately useful. Thank you.

Man even though this is not quite as relevant to me today, I really love his presentation style

Such a great video! Many thanks!

Amazing video - thank you so much!

I kept smiling. Thank you.

This lecture is very nice to learn advanced Python programming. After I watched this video, I realize that I have used Python almost like using C. I have used C and C++ as well as Matlab. Hence, I thought that many approaches in Python will be not much different from the conventional languages except specialized keywords. However, I realize that grammars in Python can be different from that in C.

I love the people who make Python! Thanks for this most enlightening talk.

This is great! I have a *much* better understanding of iterators and their purpose now. Thanks, Mr. Hettinger. edit: How did I not know about dictionary comprehensions?!? (21:05) That is AWESOME!!

I'm so glad that he said we should rename For as ForEach. I suggested that online some years ago, and boy did I get lambasted by everybody!

This was amazing!

this guy is really helpful. BLESS

this is why i love python, the ways to write clean code.

great lesson and great presenting style!!

I love this man! He should write a book on clean Python code, if he hasn't already.

He even said I would fight him on this, but haha, oh man, the comparison functions are something I absolutely *miss*, even if I really agree with almost everything else he said and have been writing idiomatic Python for ages. I ran into a real problem the other day where comparisons were a much cleaner solution than the less obvious and potentially much slower multi-pass sorting: Sorting on multiple keys with independent ascending or descending orders. You can sort a plain tuple without any fuss if you don't mind that every key is ascending or every key is descending. But if you want to mix those, you have to do it in multiple passes, starting from the least significant key to the most significant key, and rely on timsort's stability to get the job done -- or, IMO, cleaner -- if this were Python 2, I could have expressed the comparison function with appropriate ascending/descending signs in a simple if/elif/else return 0 chain, and rapidly expressed both the intent and the functional result quickly. Python 3 even provides a conversion utility that creates wrapper objects on the fly to facilitate this need, which is a bizarrely convoluted way to accomplish what simply allowing either key function or comparison function would have.

brilliant talk, thanks for sharing!

Note that these functional constructs are now in every mainstream language such as C# and Java. So, it's not that Python has a specific capability, but experienced Python programmers do encourage the use functional constructs. This video is an example.

Excellent presentation on Python code writing.

Amazing talk..more professors like him. :) I'm starting to appreciate Python now. EDIT: Wow

Amazing video, really good video and tips, thanks

Many thanks! It is still useful for me!

"with ignored(OSError)". So cool. TIL. In Python 3, it is called "with suppress(...)". You can list multiple exception types too.

I think that 'return newfunc(*args)' on line 6 must be replaced by 'return saved[args]' at 41:12

Very good video, helps writing efficient and clean Python!

So this man made enumerate()? I love him from now on!

Great presentation!

At 7:26, it should be for i, color in enumerate(colors): print i, '-->', color

What a great lecture :D

Great explanations. And even 3 years late still very useful. One thing though, he says that generator expressions make things faster but when I timeit I get this: ~$ python -m timeit "sum(i**2 for i in xrange(10))" 100000 loops, best of 3: 1.74 usec per loop ~$ python -m timeit "sum([i**2 for i in xrange(10)])" 1000000 loops, best of 3: 1.39 usec per loop

great video. thank you

Amazing Slideshow

There's an error on the slide at 7:13 titled 'Looping over a collection and indices'. Last line should be: print i, '-->', color

OMG... I have been doing hacks in python for loops trying to do what enumerate does... THANK YOU!!!

27:50 I think doing this is so common, there should be a group_by(sequence, keyfunc). You could then call it with group_by(names, len). There should also be an index_by(sequence, keyfunc). These functions would be trivial to implement, but nevertheless they are common and useful enough to be put in some standard lib (collections?).

This needs updated for Python 3 - I have to go hunting for which of his recommendations are still valid. The video could at least have footnotes that say which still applies in Py3.

Just stumbled across your video mate, really love the content. Liked straight away, We should connect!

Great Presentation.

Whenever you have a break in the for loop, just wrap that loop inside a function and return instead of break. If you want to return something else in case the for loop didn't break, just return after that loop. No need for else on the for. A for loop with a break and an else is not as readable as a function which just returns from the loop and after it.

Do we need to add a certain python library? Some codes don't seem to work, just with Python 3.6.

izip() in Python2 is zip() in Python3. Also, you can loop over the longer of the lists. So, import itertools colors = ['red','green,'blue','purple']; shapes =['circle,'triangle','square'] for col, shp in zip_longest(colors,shapes): print( col, '--->', shp) >>> red ---> circle green ---> triangle blue ---> square

Can't recommend this talk enough. Must watch to take your python chops to the next level.

I learned a lot! Then again I don't use Py3 because I use Jython which only 2.7 is stable and a compositing suite that has 2.7 also. The problem with functional programming is (and this video proves it) is that you need to know the function names and what to look for. This means actually bothering to read lots of papers and documentation and then you need to remember them. People aren't very good in remembering things especially non-descriptive. So only people who really dedicated in a language will know these things but Python is an awesome language but it's not a core programming language for most. Which is Java, C# or C++ and there you don't have a lot of functional functions. I love C because it has very few keywords, STL is great but I ALWAYS need to to reread who it works. Functionally very powerful but it's even less descriptive than these functions. So now that I know these situations explained by Raymond I will look them back here and read the docs apply them several times and probably by the 7th or 9th time I will remember it. That is until I don't use Python for 2 years again and forgotten all about them :D

43:47 "ignored" is now called "suppress" and it's part of "contextlib" library.

7:13 isnt the enumerate example 'wrong'. Shouldnt colors[i] be replaced by color?

At 41:09 - in the cache decorator definition - line 6: if we return newfunc(*args) wouldn't it cause infinite calls?

Really good video. Starts off as a video for python beginners but is insightful for experienced developers as well.

hi, new to python. when he prints on the first slide(i**2). thats exponential right? 0^2, 1^2, 2^2, right? or is that doing something else?

Is there a list sorting function with a key for frequency of occurrences?

very much required for a beginner like and why would someone dislike this ....

This guy is a legend

Most enlightening talk