Python Language Features and Tricks • Hacker News Board

Re: Python Language Features and Tricks

#11

Post by kriro » Sat, Mar 08, 2014, 4:47 PM UTC

Why are there so many negative comments? Maybe those posters are vastly underestimating how many people that just start out read HN. I think it's a pretty good post to read after something like "X in Y minutes - Python" to get a very quick grasp of what the language is like.

I'm also not ashamed to say that despite having written quite a few LOC of Python I wasn't aware of named slices for some reason and I think they can clear up some chunks of code I have produced (make it more readable)

Re: Python Language Features and Tricks

#12

Post by JeffJenkins » Sat, Mar 08, 2014, 4:54 PM UTC

It's important to remember that OrderedDict keeps insertion order, it isn't an implementation of a sorted dictionary.

Re: Python Language Features and Tricks

#13

Post by Estragon » Sat, Mar 08, 2014, 4:56 PM UTC

kriro wrote: post #11

Why are there so many negative comments? Maybe those posters are vastly underestimating how many people that just start out read HN. I think it's a pretty good post to read after something like "X in Y minutes - Python" to get a very quick grasp of what the language is like. I'm also not ashamed to say that despite having written quite a few LOC of Python I wasn't aware of named slices for some reason and I think the…

I've been using python since the 90s, and I learned a few things from this post.

Re: Python Language Features and Tricks

#14

Post by lqdc13 » Sat, Mar 08, 2014, 5:09 PM UTC

zip to unzip a dict is a very slow approach to do it

Instead of

    mi = dict(zip(m.values(), m.keys()))

Do

    mi = {v: k for (k, v) in m.iteritems()}

Re: Python Language Features and Tricks

#15

Post by k3oni » Sat, Mar 08, 2014, 5:11 PM UTC

kriro wrote: post #11

Why are there so many negative comments? Maybe those posters are vastly underestimating how many people that just start out read HN. I think it's a pretty good post to read after something like "X in Y minutes - Python" to get a very quick grasp of what the language is like. I'm also not ashamed to say that despite having written quite a few LOC of Python I wasn't aware of named slices for some reason and I think the…

Same here, learned something new today.

Re: Python Language Features and Tricks

#16

Post by dkersten » Sat, Mar 08, 2014, 5:16 PM UTC

robinh wrote: post #7

I have two questions. 1. I'm unfamiliar with the term 'unpacking'. Is it any different from pattern matching in, say, Haskell (but perhaps not as feature-rich)? 2. Aren't slices pretty much a staple in Python? I didn't think using them was considered a 'trick'.

Unpacking is a limited form of what is called destructuring in other languages like Clojure. I would say that, in terms of feature-richness: unpacking < destructuring < pattern matching.

Re: Python Language Features and Tricks

#17

Post by sillysaurus3 » Sat, Mar 08, 2014, 5:34 PM UTC

odonnellryan wrote: post #5

jkork wrote: post #4

patterns / tricks = language deficiencies Wake me up when Python will support tail call elimination and will get rid of GIL. For now this language is no better than PHP.

For TRE: http://neopythonic.blogspot.com/2009/04/tail-recursion-elimi... For the GIL, there are alternative implementations of Python (Jython, IronPython, etc.)

Hm... Python only supports 1000 recursions? That seems unsafe. It seems like anyone who writes functional-style code will run the risk of a stack overflow.

Re: Python Language Features and Tricks

#18

Post by Bocker » Sat, Mar 08, 2014, 5:37 PM UTC

kriro wrote: post #11

Why are there so many negative comments? Maybe those posters are vastly underestimating how many people that just start out read HN. I think it's a pretty good post to read after something like "X in Y minutes - Python" to get a very quick grasp of what the language is like. I'm also not ashamed to say that despite having written quite a few LOC of Python I wasn't aware of named slices for some reason and I think the…

I've been programming in Python for about 3 years and learned a couple of tricks from this post, which was why I submitted it.

There's always tricks to learn, and it's hard to remember everything when you're first starting out with a new language.

Re: Python Language Features and Tricks

#19

Post by mildtrepidation » Sat, Mar 08, 2014, 5:41 PM UTC

lqdc13 wrote: post #14

zip to unzip a dict is a very slow approach to do it Instead of mi = dict(zip(m.values(), m.keys())) Do mi = {v: k for (k, v) in m.iteritems()}

When did support for dictionary comprehensions make it into 2.x? I could've sworn it didn't used to work, but I just tried it in the shell and sure enough, it does in 2.7.3.

Re: Python Language Features and Tricks

#20

Post by mildtrepidation » Sat, Mar 08, 2014, 5:44 PM UTC

jkork wrote: post #4

patterns / tricks = language deficiencies Wake me up when Python will support tail call elimination and will get rid of GIL. For now this language is no better than PHP.

No better than PHP? That's more than a little ridiculous. Every language has shortcomings, and there's no silver bullet/perfect multitool that can or should be used for everything.

It's too bad it's apparently not good for... whatever it is you do. It is pretty great for some things, and having spent more than a few years with both Python and PHP, I can say without reservation that there is absolutely no comparison in terms of language quality.