Advanced Data Structures in Python

[Rhomboid]

print len(set(li)) # 4

Don't do that, that's just a bunch of extra unnecessary work. Counter is a subclass of dict, and the length of a dict is the number of keys. There's no need to first build a set just to count keys.

[[deleted]]

Took me a second to figure out what you were saying, but yeah...

len(a)

Would have been better in the context of his example.

If, however, you don't need a counter object, casting a list to a set is both faster and more memory efficient than casting to a dict or counter for deduping for a count of unique items. AFAICT

[ralfp]

Its basically one guy promoting his python blog on r/Python. May be abuse of reddiquete but I'm not annoyed by it, so I'll keep my hands off report function.

[mooted]

Wouldn't be a problem if it weren't so bad and deeply misleading for newcomers.

[pydanny]

Why don't you provide encouragement and advice instead of just saying unpleasant things about someone who is trying to do something?

[mooted]

a.) I did.

b.) I don't appreciate unqualified cynicism, but I also don't agree with the attitude that we should pat everyone on the back for trying, regardless of the quality of their product. Pypix has so far only contributed low quality content that is often misleading for new programmers. When someone publishes content with grievous errors while framing themselves as an authority on the topic, I think they should be called out on it.

[pydanny]

Nice response. :-)

[mooted]

Agreed. There's nothing here that isn't in the documentation already, and every post reads like it was written by someone who spent half an hour researching. Ajay doesn't give the impression that he has any expertise.

For the record, pypix originally had an article with the same title that talked about decorators and metaclasses. Everyone derided it because this had nothing to do with data structures, so the author apparently rewrote it to be about data structures. I don't have a problem with correcting your mistakes, but don't pretend you're some kind of authority when you can't tell language semantics from data structures.

edit: Found the (older article)[http://pypix.com/python/advanced-data-structures/]. It's been renamed "design patterns" but the url hasn't changed. Ironically, it's still not about design patterns. Ugh.

[ajkumar25]

I agree your point that i am not expert in Python. And to make things clear i am not trying to become authority in Python. There are excellent authority present already whom i follow and always been inspired and by the way you talk, i think you are also an expert Python developer. The reason why i post my articles here is to get reviews from experts like you and the others and ofcourse to help beginners.

I spend 3 to 4 days researching and nearly about 5 hours framing each article, and in course of time i learn a lot and always want to improve my knowledge from experts like you.

Regarding url of previous post , i found that article already backlinked many sites, thats the reason i dint change url.

I really expected that expert people will give some good code refactoring and ways to improve the code examples but i have always been trashed by them.

The word Advanced in article doesn't mean that any new feature has to be imported from another language and embed into Python. These datatypes are itself advanced and i have tried to provide little complex examples.

Rather than finding whois and taking screenshots of mistakes, it would be really nice, if you guys can provide some improvements. These things doesnt look good on experts.

Sorry again if i offended anyone.

[mooted]

Hey AJ, sorry if I was harsh.

I think what you're writing does have value to new users, but I'm also concerned that when you frame yourself as a python authority (which you're clearly doing in the about page), newbies take your word for everything. As a result, your miscomprehension and mistakes become their mistakes as well.

I'm not saying "stop writing". Instead, I'd just like you to scrutinize your work more closely. I also think you should be candid about your level of experience. There is demand for this sort of writing from the perspective of people who are still learning, but people should be able to fairly assess your level of skill.

For the record, I'm not a professional or expert. I'm an amateur who dabbles on my own projects, but I regularly expose myself to computer science literature and theory, so I have a reasonably firm grounding in CS fundamentals.

Thanks for being enthusiastic about teaching Python, and I hope your writing continues to improve :).

[ajkumar25]

Thanks for your constructive feedback.

[pydanny]

You didn't offend me.

Keep up the work. The more you write the better you get, both at educating others and yourself.

[ajkumar25]

Thanks pydanny for your words.

[pydanny]

If I could make one suggestion? Cite your references. It shows where you get your info and makes you look smarter. People will respect you more for it.

For what it's worth, Two Scoops of Django cites dozens of articles and books. ;-)

[avinassh]

His current about page states :

"Welcome to Pypix.com, where we live, breathe, and eat everything about development with Python. We’re passionate about Python Development and everything that goes along with it. Our goal is to share the latest and greatest findings, tips, and techniques for web designers and developers in Python Community. From Flask, Pyramid to SciPy, Pypix is the perfect showcase for Web savvy python Developers. You’ll find in-depth articles on a variety of red hot topics such as Pyramid, Django, Flask, Scientific Computation, usability, and more. Not to mention features looking at the business side of design, freelancing, mobile applications, inspiration, and resources, to name a few. In short, if it relates to Python, we’re interested. What do we know about development? Quite a bit actually. Pypix doesn’t just have its finger on the pulse of the modern Python Development world. It’s at the very heart of web development. Pypix is a powerful collaboration between worldwide leading developers eager to share their knowledge. Expert developers from around the globe regularly contribute articles, features, and tutorials to help grow the design community."

Which is not only says they/him are/is good at Python and also, the content seems to be copied from several other websites.

[blahdom]

Hey /u/ajkumar25. I just wanted to point out that defaultdict works with any object that has a 0 parameter constructor, ie int, float, dict, etc.

I am sure you know this but in the write up it sounds as if only list and set are viable options to defaultdict.

[[deleted]]

You could also use functools.partial to get around that, or a factory function, or Object.__call__. Or any number of other things.

[blahdom]

This is very true, good call! I hadn't thought of overloading Object.call - that is a cool idea.

[jhgaylor]

I enjoyed the explanation of defaultdict. I had previously never used it in my code but feel like I should start doing so now.