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Now located at

Why it was moved

Github gists don't support Pull Requests or any notifications, which made it impossible for me to maintain this (surprisingly popular) gist with fixes, respond to comments and so on. In the interest of maintaining the quality of this resource for others, I've moved it to a proper repo. Cheers!

Very useful. Thank you.

This is wonderful, thanks for documenting this!

frodon1 commented Oct 12, 2015

Hello !

Do you know if there was a reason this following code was not proposed ?

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

instead of

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

@frodon1 Raymond Hettinger actually mentioned that this example can be simplified using an early return. See video. He said that for...else can be useful when a situation like this occurs "intermeshed with other more complex code in other operation so there is not a shortcut out".

I added notes for python 3 users. Could you please pull this changes?


JeffPaine commented Dec 28, 2015

@mongoose11235813 Thanks! You're changes have been merged. Sorry for the delay. Some searching turned up that github doesn't have notifications for comments on gists :(

For my (or other's) future reference on how I merged in the changes from your fork (since gists don't support pull requests):

 git remote add mongoose11235813
 git fetch mongoose11235813 
 git merge mongoose11235813/master 
 git push origin master

greut commented Mar 11, 2016

There is yet a better way of counting things:

Hi, under "Using decorators to factor-out administrative logic" can you @JeffPaine please fix the if statement?


Nice to see this written. Please change dicitonary keys to dictionary keys.

It's so useful! Thanks


JeffPaine commented Jun 27, 2016

@robinchew: done, thanks! 😃

@DimitriPapadopoulos: Done, thanks! 🍰

All: glad everyone is enjoying and learning from this write up. Raymond Hettinger really gave a wonderful talk here!

Thanks for the notes @JeffPaine!

jhadjar commented Sep 24, 2016

That was a great talk. The ratio content/time was huge. There's someone in the video comments (DarthChrisB) who time-stamped the video with each topic.

Thanks for sharing.

SF-Zhou commented Oct 10, 2016


ZuZuD commented Dec 4, 2016

You should precise the library for defaultdict, influence, deque... Good job thank you !

Thanks for sharing.

pybites commented Jan 10, 2017

this is awesome, thanks!

Typo on "Factor-out temporary contexts":

yield fieldobj

Thanks so much for writing this up! I actually had just started to do the same, but then decided I should at least check online to see if anyone else already had!

I see @ikem-krueger mentioned this but you have a typo with the redirect_stdout function. It should yield fileobj instead of 'fieldobj'.

You can fork my fix below:

jellyjellyrobot commented May 16, 2017


Thanks for sharing. This really useful!

This part is not working (even indentation fixed)
Consider updating from my fork:

zenware commented Aug 7, 2017

# First we are shown this as the better way to reverse,

# And then this is shown for reversing sorted elements
sorted(colors, reversed=True)

# Why not this?

I'm sure there's a perfectly good reason, like, "There's an algorithm with which sorting and reversing 
can be done together, faster than they can be done apart.", I just think that it should be made explicitly apparent.

Hey. Small typo: explicidly -> explicitly.
Thank you very much.

List Comprehensions and Generator Expressions

result = []
for i in range(10):
s = i ** 2
print sum(result)

IndentationError: expected an indented block

Factor-out temporary contexts

def redirect_stdout(fileobj):
    oldstdout = sys.stdout
    sys.stdout = fileobj
        yield fieldobj    # 'fieldobj' may be 'fileobj'?
        sys.stdout = oldstdout

JeffPaine commented Dec 3, 2017

I've addressed all comments here and moved this gist to a proper repo: (so Pull Requests can be received and I get notifications, which isn't possible for gists).

If you have any other fixes / comments, please make them on that repo as I won't be checking back here again in the future. Thanks a lot!

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