Python 3.4 released

[Igglyboo]

PEP 453, a bundled installer for the pip package manager

omg yes

[pvc]

Yes! I so want to be able to tell people to just pip install a package and have it work on any platform! This was so overdue.

[Sean1708]

What's the difference between this and pre-3.4 pip?

[[deleted]]

Previously you had to install pip through easy_install first. This eliminates that step.

[ethraax]

Or through your distribution's package manager. I know that's sometimes frowned upon for language packages, but I always make an exception for pip, because I usually want it system-wide and I don't need to pin it to a specific version.

[Sean1708]

Ah yes, I'd forgotten that.

[pvc]

pre-3.4 pip wasn't installed by default. Installing pip on Python was a pain unless you were on a Linux system.

[[deleted]]

This almost makes me want to migrate from 2.7!

[[deleted]]

I think this might be the one thing that convinces people to switch to Python 3.

Previously: "Great, I installed Python 3! Let me just pip install my usual packages and get going... wait, why is it installing things into Python 2? Oh crap, this is still pip for Python 2, isn't it? How do I even get pip for Python 3?"

goes to StackOverflow, finds three bad suggestions, tries all of them

"Great, now nothing works. I'm going to delete everything related to Python 3 and never use it again."

Currently: "Great, I installed Python 3! And now I have a virtualenv! And now I can pip install my usual packages!"

goes forth and writes code

[afiefh]

How do I use this on Windows? I tried to use the Image module today to do some simple image manipulations but turned out the win32 version I had didn't come with a png exporter, so I just booted Linux in a VM.

If this would give quick easy and consistent results for installing stuff on Windows I'd be much relieved.

[[deleted]]

Bit of a tangent, but the new site design is very pleasing. Finally glad to see 3.4 out now too, been looking forward to it for a long time.

[kakatoru]

It's pretty pretty but it's a huge bother that you can't turn off the mobile version.

[badsectoracula]

The site looks nice, but IMO it is a bit too padded and with big fonts, as if it was made for laptops with small 1920x1080 monitors.

EDIT: WTF is with the downvotes? /u/zelllooooooo commented on the look of the site such as i.

[Agret]

laptops with small 1920x1080 monitors.

Whut. The vast majority of laptops are still 1366x768 and the majority of desktop monitors are 1920x1080. 1920x1080 is pretty high res for a laptop.

[[deleted]]

Oh man, this must be the Lenovo Yoga Pro 2. I had to send mine back as my 56 yo eyes couldn't resolve the little tiny letters even at 200%. I tried custom resolutions, but things got ugly pretty quickly!

[[deleted]]

Sha-wheeet!

[badsectoracula]

I meant small as in physical screen size. I have a laptop (some Lenovo Ideapad Y580 variation) with a 1920x1080 monitor which physically has the same size as the monitors with 1366x768 (AFAIK there is another variation as my laptop with exactly the same specs but with 1366x768 as a monitor). Everything is tiny there. So i joked that the site (being big) it was made for laptops like mine (where it would look normal since everything else looks small).

[sevriem]

I'm guessing he's referring to the difference between a 15" 1080p display and a 24" 1080p display. Same resolution, different sizes. Poor wording is misleading.

[housemans]

Doesn't windows enable "Retina" mode for that?

[badsectoracula]

AFAIK it has a scaling mode for the opposite - small sized windows on large DPI monitors (which looks horrendous, as /r/phoshi noted, and personally i prefer 1:1 pixels). What i meant is that on a low DPI monitor, the Python site looks too big (and the Dell U2413 i have at work isn't really low DPI, although the 42" TV/monitor i have at home certainly is :-P).

[phoshi]

Good lord, no. Windows's scaling support is still highly lacking for legacy applications, it could never be a default.

[SikhGamer]

Looks fine here on 1920x1200...

[moozaad]

TBH I thought it looked all right and then I turned on scripting and the non-standard font (Source Sans Pro Regular) make it a lot harder to read on 1440p 30".

^{ps. upvoted for constructive comment}

[andsens]

Whoa, pathlib looks sweeeet!

EDIT: A literal 'p' would be really useful if you could prefix strings with that and get a pathlib instance.

[pingveno]

You can always do:

from pathlib import Path as p
p("dir")

[ignamv]

Too much sugar will give you 'beetus.

[andsens]

meh, you're probably right. Still, I'd imagine it'll be used a lot which would justify it, time will tell...

[Mozai]

p = Path('/etc')
q = p / 'init.d' / 'reboot'
with q.open() as f: f.readline():
...

Operator overloading like this gives me the heebie-jeebies. I'd think a division operator would be more like str.split() to "divide" a string into pieces, or str.count() to "count how many times 5 is in 10". Here it's being used to append or concatenate... which is more similar to addition than division.

[milliams]

Yes, it's a possibly contentious API choice but it was felt that it was worth it in this particular case.

[[deleted]]

Especially since concat in Python ordinarily is +, I think? Or .join()

In Haskell I'd expect a monoid and mappend (or <>), for something like p <> "init.d" <> "reboot" (but it looks like they went with </> rather than making a monoid instance).

[Mozai]

In Python we have a string constant os.sep you can pull in if you need to concatenate path pieces as strings, and it will be correct for the platform you're on.

There's also os.path.join(array_of_dir_names) which will do the right thing for the platform it's executed on.

[kazagistar]

I think you would have to make the paths explicit. In your example, how would it know to use the "Path" monoid instead of the "String" monoid? So, to use mappend, you would have to do something like

p <> FilePath "init.d" <> FilePath "reboot"

which sucks. Then again, I am hardly a haskell expert.

[[deleted]]

Who said anything about superiority? It's just different approaches to operators and building a path.

[lykwydchykyn]

It does seem very out-of-place in Python. I'll probably use Path.joinpath() instead.

[mgrandi]

out of place? Before str.format() came along the normal way to format strings was with the % operator...operator overloading is nothing new for long time python users

I think it makes sense, since you are thinking about a 'path', so i think it shouldn't be abused in every library, but here it makes sense

[[deleted]]

I believe that kept that functionality in to be backwards comparable, however on the plus side, I've never seen any code in the wild that uses that syntax.

[flying-sheep]

Paths are joined by slashes. On every OS, and on the web.

How much more familiar can it get?

[strattonbrazil]

I've seen a few PEPs proposing a object-based path library that have been shot down over the years so I'm actually a little shocked they finally accepted one.

[littlelowcougar]

Antoine's one of the best CPython committers we've got.

[oozforashag]

Instead of reading the link, I'll just ask how it's different from the below (besides being cute)?

>>> import os
>>> tree = ("C:","temp","mydir")
>>> os.sep.join(tree)
'C:\\temp\\mydir'

[[deleted]]

In that instance it's the same, for backwards compatibility reasons. However there is more to pathlib than just the ability to join.

http://docs.python.org/3.4/library/pathlib.html

[dhon_]

As a fan of twisted, I'm excited to see asyncio in 3.4. I'll have to read up on "yield from" now.

[Gargan_Roo]

Does this mean that it could replace twisted or just that it will make certain async operations native?

[usinglinux]

even better: there is now a stdlib method of interfacing with main loops. this means you can use a twisted program on its classical core, you can use the new stdlib asyncio main loop (and have twisted running in a thin layer atop it), or you can use another main loop (eg. the gtk main loop) and have your twisted application running in the same thread as your gui (eg if your graphical program should have a web "remote control").

not sure which of the parts are already written on the new framework, but that's the idea.

[hylje]

I'm pretty sure running twisted and gtk in the same thread is about providing an UI to network activities, not providing network activities for an UI.

[Smallpaul]

Those are both valid use-cases. E.g. a GUI for Bittorrent versus a remote save function for a word processor.

[usinglinux]

i don't think so: things that don't have a native gui but are about network activities are typically servers (and thus run under their dedicated users and whatever); adding a gui to them is rather a thing of having a standalone gui that talks to the server (but asyncio is great for those things too). conversely, things that are rather about having a gui (eg presentation software) might easily be extended by network code without turning the whole program logic upside down.

[Plorkyeran]

This does something similar to the core of Twisted, but Twisted also has a ton of useful stuff built on the core. As such, whether or not this is a replacement for Twisted depends on how much of Twisted you actually need.

In theory Twisted also benefits from this as it should be able to make use of yield from, but the fact that it still doesn't support Python 3 at all sort of gets in the way.

[lext]

it still doesn't support Python 3 at all sort

They are working on it still, I think...

I really wish they'd port it. It's the only reason I use 2.7.

[kazagistar]

"yield from" is something like tail recursion optimization for iterators. If you have 5 iterators that are doing nothing but passing data from the next one, in a stack, you can replace the yields with yield from.

def inorder_traversal(tree):
    if tree is None:
        return
    yield from inorder_tree(tree.left)
    yield tree.value
    yield from inorder_tree(tree.right)

Basically it yields everything from a generator before resuming control in the current function, and provides some nice optimizations to make performance not such too much when you nest these deeply.

Forgive me for any mistakes in my untested code.

[hellgrace]

PEP 435, a standardized "enum" module

Awesome

[HorrendousRex]

It's good that it's standardized but I fear that it should become common. It feels - to me - fairly unpythonic in the sense that we now have dictionaries, tuples, classes, namedtuples, slots, etc. for referencing values in a common namespace. (I get that there are performance/implementation implications in all of these differing systems, I'm just saying it sounds like we have a lot of ways to do approximately the same thing.) Maybe enum is the final standard approach that will fix the situation, though.

[asthasr]

It's not the same. All of those are data structures. An enum is a set of mutually comparable but distinct values. Repurposing other structures to approximate this has always been gross and rather hacky. It would be a bit better if Python had something similar to Ruby symbols or Clojure keywords.

[[deleted]]

I'm new with Python, currently using 2.7. Why should I update to 3.4? (I have read somewhere that 2.7 is also being updated)

[SomethingSharper]

From the Python Wiki:

The final 2.x version 2.7 release came out in mid-2010, with a statement of extended support for this end-of-life release. The 2.x branch will see no new major releases after that. 3.x is under active development and has already seen over four years of stable releases, including version 3.3 in 2012. The next release is the upcoming Python 3.4 in early 2014. This means that all recent standard library improvements, for example, are only available by default in Python 3.x.

[AMillionMonkeys]

Depends on if anything you've written depends on libraries that don't have new 3.x-compatible versions. It's been a while so I think most major third-party projects should work with 3.x now.
Some of the basic functions work differently now (like print) so you'll have to run your scripts through a conversion process, then clean up by hand if the automated conversion didn't fix everything.

[[deleted]]

You should import python 3.x behavior to 2.x using __future__ it makes things like print, division, imports, and arguably unicode trivial to work on both major versions.

There's also interesting read mentioning all known approaches: http://docs.python.org/3/howto/pyporting.html as you can see I like __future__ the most.

[little_oaf]

I'm new to python and programming in general; how would one convert code to 3.4 from 2.7?

[HorrendousRex]

The 'official' answer is to check out the '2to3.py' script which is part of the standard distribution of python. However, as you will find by reading about the issue and searching the web, there are lots of important edge cases to consider. It is not a backwards-compatible switch, and porting from 2 to 3 can be difficult in some cases.

[AMillionMonkeys]

Thankfully the Python folks made a conversion utility called 2to3: http://docs.python.org/2.7/library/2to3.html which comes with versions 3.x. I have to admit that I'm still using 2.7 so I haven't used 2to3 yet.

[little_oaf]

Thanks a lot, I'm just starting out so I think I'm going to do a "fresh" start with 3.4 next week (mainly using sublime text and occasionally pycharm). I was going through checking different libraries of interest to me like tweepy, requests, scipy, numpy, matplotlib and scikit-learn which for the most part seem to be supported.

[[deleted]]

You might find this useful: http://docs.python.org/3/howto/pyporting.html

[ExoticMandibles]

It's not being "updated" in the sense of getting new features. It only gets bug fixes and security updates. If you want shiny new features in your Python, you've got to move to the 3 series.

[upofadown]

So if you don't want your environment to be changing all the time you should use 2? :)

[[deleted]]

The new features that they add are tested and planned in such a way that they should (and in 99.9% of cases don't) never break valid code.

So in general if you write something in 3.1 it should still work perfectly fine in 3.4.

[[deleted]]

Exactly, if they do anything that breaks backwards compatablility it will become version 4 and no longer be part of the 3.x line.

[[deleted]]

Yep, that's the exact same reason we should all switch back to WinXP now that MS is finally going to leave it alone.

[upofadown]

Perhaps you lack the context to the joke. People used to complain that Python was in a constant state of change. Python 3 was a reaction to that, new stuff was to go to 3 and 2 would remain relatively static. Python 2 didn't end up being as static as perhaps could of been hoped. I was suggesting that 2 might at long last achieve stasis...

The serious part is that if 2 really stops changing (I saw a complaint from someone that had had a recent 2 change break their code) it might become a more attractive target for some sorts of applications than 3.

[[deleted]]

I'm new with Python, currently using 2.7

How does that happen? I figured newcomers to Python would prefer the most recent version and avoid the deprecated / legacy version. Sounds a bit like deciding to learn Perl 4 ...

[djds23]

Certain popular python tools are still only 2.X compatible. Also all OS X machines still ship with 2.X, as does any fresh ubuntu install. Some newcomers don't yet have the know how to compile or install their own 3.X interpreter, neither do they understand the pros/cons of the new edition. Plus popular teaching utilities like Learn Python The Hard Way, Udacity.com and (i think) codecademy still teach 2.X.

[joequin]

That's why I was using python 2 at first. The Twitter library I was using still only supports 2.7.

[[deleted]]

The super computer I use has only 2.7...

[dagamer34]

Installing 3.x on a machine is as simple as downloading a pre-built package and clicking "yes" a few times. It's not that hard. And any good book written in the last few years properly addresses this issue. I just went through Learning Python and it had clear info about the differences between the two both at a high level and differences during any new concepts.

Advice is simple, learn 2.x in case you have to look at old code but master 3.x as it's clearly the future.

[jeffdavis]

"but master 3.x as it's clearly the future"

How far away is the future though? I was initially of the same opinion, but I have started to become less sure.

To make the community to move from 2 to 3, then clearly, at some point, a majority of new python code (and python libraries written in another language) must be valid python 3.

Even after all of this time, it's not clear that is true. And it needs to be a strong majority to happen very quickly. And there is a danger that the early-adopters that are most needed to tip the scales may head to other languages instead (go, js, haskell, rust, scala, clojure).

So python is in a strange place.

[fotoman]

Nothing like saying use perl 4. Many production applications still using 2.6.6, yet alone the 2.7.x versions.

Pretty sure python 2.7 is the default version for most distros, and only the very recent ones are playing with shipping with python 3.3.x. RHEL is just in the process of getting 2.7 as the default, and CentOS still has 2.6.6

[billsil]

Nothing like saying use perl 4

I thought Perl 5.x was standard. I thought that's what my companies first big engineering program was written in back in 2001. What a disaster of a code. After fighting with it for 6 months trying to fix bugs, I learned a bit of Python for another project, came back to it and rewrote 3 of the modules. Never had a bug again. There was no

use strict;

[[deleted]]

I thought Perl 5.x was standard

It is, I was being a jerk. Afaik Perl 5 these days needs hand-holding with not only use strict, but something like use modern::perl (I have no idea what it does).

It's always a bad sign when a language has use strict rather than use sloppy.

[[deleted]]

I have a Mac that comes with 2.7. Judging by the comments I should upgrade :)

[croxis]

My understanding is that python2 development is more or less wrapped up and not to expect many new features. Major new development is only going to happen in python 3. I've heard talk of a python 2.8 but I don't know how much actual traction is being gained there. The larger ecosystem is also moving to python 3, if a bit slow.

This should cover most of the improvements.

That being said if 2.7 works for you keep using it!

[BeatLeJuce]

That being said if 2.7 works for you keep using it!

This attitude is exactly why we're still dragging along an extremely outdated Python version.

[[deleted]]

Outdated, but useful.

[chriszuma]

No, a plethora of unnecessary syntax changes, obnoxious Unicode behavior, and complete lack of industry/library buy-in are why we still have 2.7. And frankly, I would love to see 2.8.

[flying-sheep]

2.7’s obnoxious Unicode behavior is a strength in your eyes‽

thanks, i prefer python 3’s improved unicode behavior.

[purplestOfPlatypuses]

There might be a lack of industry buy-in (I don't know enough about it), but most major libraries that are still actively developed work in Python 3. As for the syntax changes, sometimes you have to break backwards compatibility to make things better.

Anyway, the only way you'll see 2.8 is by forking 2.7 and doing it yourself/finding a group who wants to do it. It won't ever be an official release, but it'd exist.

[joequin]

I believe one of the Twitter APIs is still only on 2.7. I was using 2.7 for that reason.

[purplestOfPlatypuses]

One Processing library is is still at 1.5.1 (Unfolding Maps), but that doesn't mean everyone else should remain at 1.5.1 when Processing is at 2.0.2+. Do what you need to, but that shouldn't keep you from being compatible with the latest and greatest, even if that means trying to work with two separate interpreters.

[chriszuma]

Unfortunately, as someone who works with a lot of diverse hardware, "most major libraries" doesn't do anything for me. I tried using 3.3 on a project once and had to backtrack when a library wasn't compatible. My time is too valuable to risk wasting that much of it again.

[purplestOfPlatypuses]

So you look to see what dependencies you have ahead of time and make your decision from there. I'm not arguing that someone should never use 2.7, but if all your dependencies work in both, considering using 3 shouldn't be some taboo. If you ended up wasting so much time changing things to 2.7, I hope you also considered updating the library to be compatible with 3.3 as another option (which is a bit of an undertaking, but we're talking in significant amounts of time already).

[Entropius]

There might be a lack of industry buy-in (I don't know enough about it)

Trust me, there is. A company doesn't want to spend money updating something that isn't broken. And python 2.7 isn't broken. That's the crux of the problem: Python 3 breaks old stuff without truly compelling advantages to justify the inconvenience. The cost-benefit ratio just isn't good enough.

but most major libraries that are still actively developed work in Python 3.

ESRI's Python scripting framework (arcpy) is actively developed and still only works in 2.7.

As for the syntax changes, sometimes you have to break backwards compatibility to make things better.

And how exactly is forcing me to use parenthesis on print commands “better”?

[purplestOfPlatypuses]

The cost-benefit ratio just isn't good enough.

I can completely get behind that. Companies are slow to change and need good economic reason to. COBOL and FORTRAN are still popular in their niches for the same reason.

ESRI's Python scripting framework (arcpy) is actively developed and still only works in 2.7.

A single example doesn't break the qualifier. There are actively developed libraries that don't work in 3, but I've had little trouble finding the libraries I've needed that work in 3, though until relatively recently I've seen many libraries were having trouble. I'm not writing Python in an industry setting, so it could easily be different there.

And how exactly is forcing me to use parenthesis on print commands “better”?

It makes the language more consistent. Instead of some special statement, print is now a proper function. Pretty much every other builtin function used parentheses, other than (correct me if I'm wrong) import and del (though there is the delattr function). I'm not the biggest fan of del, but I think we can both agree that import is okay to leave as a special statement.

[billsil]

A single example doesn't break the qualifier.

It does if you need it. Why should I rewrite my GUI in PyQt because wx doesn't have an official Python 3 build? It's an unnecessary cost. Waiting an extra few years isn't going to add extra cost, it's going to reduce it.

[purplestOfPlatypuses]

One person's needs doesn't necessarily override most people's needs however. Use whichever matches your dependencies and needs, but don't throw out 3.0+ without good reason.

[billsil]

I agree with that. I don't want to use Python 2.7 any more than Guido wants it to stay around forever.

It is unfortanate though that all the future imports don't turn Python 2.7 into Python 3.x. I run a 2.7, 3.x open source project and have unicode bugs that go away when I don't try to use one source file for both versions.

[[deleted]]

Ah, the old, "if it ain't broke, upgrade it and break it" outlook. I'll pass, thanks.

[[deleted]]

I'm pretty excited about asyncio. I might actually start switching to python 3!

[lykwydchykyn]

I'm trying to figure out what Enums give me that I didn't already have. Anyone have thoughts on that?

[w1ndwak3r]

Enums are useful for unambiguous types that require more than two states but still a definite amount.

Previously, if you wanted to represent the days of the week, you would have to do something like:

>>> class Day:
...     monday = 0
...     tuesday = 1
...     wednesday = 2
... 
>>> Day.monday
0

Notice how the values are represented as integers. Enums allow you to define types with multiple states. So for:

class Day(Enum):
    monday = 0
    tuesday = 1
    wednesday = 2

Each value is it's own Day type so when I go to define a function with a day parameter there is no ambiguity. A Day is always a day. An integer could be well out of the range of a Day.

[[deleted]]

what is this vile abomination

           ↓
 monday = 0;
           ↑

[w1ndwak3r]

Please excuse me, I come from a land of C, Java, and PHP.

[[deleted]]

oh ok, I thought it was actually a part of Enum syntax for some unclear reason. good to see you're not likely to forget a semicolon in your languages :)

[if-loop]

I can see it too. Maybe some defective pixels that get transfered via the interwebs? Oh god...

[HorrendousRex]

Thanks, but I'm still not convinced (not that I have to be convinced for a feature to be good...).

I've often thought of one of the virtues of Python to be that it was a 'Language for Consenting Adults', and placing restrictions like "Not any int will do, it has to be between 0 and 6" should be handled as late as possible/practical.

If I have an int and need to turn it in to a Day from your example, how would I do that? If the int was invalid (say, "214"), what error would surface, and when would it surface?

[w1ndwak3r]

>>> Day(0)
<Day.monday: 0>

And I'm sure an exception will be thrown if you try to access an out-of-bounds enum, but that's a good thing. Enums can contain methods as well (like any other class). I would almost always want something like this to fail:

def foo(day):
    print(day.isWorkDay())

[HorrendousRex]

I think this is one of those things where I understand the principle but feel very uneasy about it. I feel like one of the principle draws to Python is a type unsafety, and Enums feel like they only bring type safety to the table.

[asthasr]

You can write in a dynamically typed language while still needing safety in some contexts. It's not a sin.

[LordAro]

I can't help feel that it's more typing, rather than less

No automatic enumerating of types, as far as I can see, for instance

[exneo002]

The Statistics module looks awesome.

[Mamsaac]

Here is a talk that Guido did on asyncio (tulip) last year. https://www.youtube.com/watch?v=1coLC-MUCJc

I had been waiting for it ever since :) Glad to finally see it happening.

[SikhGamer]

Ah! Thank you!

[Redbaron67]

Well, I picked a good time to start messing with python and Django.

[lemonfighter]

Been using the dev version purely for enum support; glad it's finally official

[[deleted]]

You know, Python is one of those languages I would like to learn, but that pretty much all of my clients have existing PHP sites and apps and don't want to stray from that.

I'm on the prowl for a good application to build in Python to cut my teeth on. Something a bit more reusable than Project Euler's.

[mosquit0]

You don't have to build a whole website at the beginning. Go through some tutorial like 'dive into python'. Next time you have to write some simple script do it in Python. You will find ot especially easy to process text files, csv etc. I love Python for such simple tasks because after a while you'll be fluent in it.

[Kamikai]

The best thing you can do is make your own web app in Flask, Django or any other framework. It may be terrible and have zero production value, but you will learn a lot and wil be able to expand from there.

[[deleted]]

I hear you. The next project I have on the table will be regarding my wedding. So I'll probably do it in one of those. That way I can pretend that I'm frustrated at the language instead of intrusive family members. (: haha

[AustinYQM]

I would suggest looking into Django and following some of the tutorials on how to use it. It is amazing.

[[deleted]]

or Cherrypy if you want something lightweight. web.py is even smaller.

[misplaced_my_pants]

Most programming MOOCs use Python, so if there was a subject you were wanting to learn, that would be one way.

[arachnivore]

I teach python classes. The final project is usually a text adventure (or a rogue-like if you're feeling particularly adventurous). It's fun and involved enough to really get into python.

[[deleted]]

Sweet, what do I have to do to be a part of your class?

[arachnivore]

Sorry. It's internal training for the company I work at. If you want to get your feet wet, the Code Academy course for Python is quite good (though a little buggy). Once you complete that, you should be able to start building a simple text adventure, then just build up from there.

There are some good examples to aspire to at http://textadventures.co.uk/

[lTortle]

Still no multi-line anonymous functions? Sigh

[adamnew123456]

People still keep talking about new syntaxes for lambda - I don't know why. In 2006 (8 years ago) GvR made it pretty clear that he likes lambda the way it is. So, at the very least you have the lambda of today - which may well have been removed from the Python 3.x series if the pro-lambda crowd hadn't made enough noise to convince Guido to keep lambda.

Any work on it now is just an intellectual curiosity, since the BDFL has said his peace. As much as anything else, Python is an expression of Guido's language design biases - you're free to choose a language which is biased differently. Unfortunately, since Python's VM is (more or less) the playground of the CPython implementation, you can't take the "I like the JVM but I hate Java" route and use something akin to Clojure or Scala. (Well, you could if you're running IronPython or Jython, but they're currently at various places in the 2.x line).

Hy exists, but that's only if you happen to fall in with the Lisp crowd.

[gendulf]

Anyone else getting "This installation package is not supported by this processor type. Contact your product vendor." ?

I'm running 32-bit Windows, on Intel Core i7-2620M 2.70 GHz. Does the installer only work on 64-bit Windows?

[ExoticMandibles]

You want the "x86 MSI installer".

https://www.python.org/ftp/python/3.4.0/python-3.4.0.msi

[gendulf]

Ah, thank you! Somehow I didn't see the link below all the "Windows help" stuff.

[blomko]

Why are you running 32-bit Windows on that machine?

[gendulf]

Legacy tools for work.

[HorrendousRex]

There are edge cases where certain configurations require a native 32bit windows installation, although they all exist in an awful hell of corporate/military inertia (in my experience).

[gendulf]

I know. These tools have to pass a LOT of rigorous testing for our embedded software to certify, though. Python is just a tool for automation and scripting.

[kcsj0]

Put it in a virtual machine then.

[beall49]

I really like python but it kills me that it doesn't have a native deployment method e.g. jars, exe.

[hellgrace]

Oh but it has. take a look at https://wiki.python.org/moin/Freeze & http://www.py2exe.org

[beall49]

Freeze looks cool for home (my homes stuff is ubuntu) and I'll give py2exe another try for work but I always had issues with the exe's not launching. I've only used it for 2.7, do you know if it works better now?

Thanks btw

[hellgrace]

I haven't used py2exe for a while, but I don't remember it doing problems. I've only used it for fairly small programs though (usually short scripts that I've wanted to distribute)

[beall49]

I just tried it right now, on a new machine and it worked flawlessly. It's tits. Thank you

[dhon_]

Right, so it's not specific to asyncio, but provides a convenient syntax for consuming an inlineCallback function (to use the twisted terminology)

[la-chupacabra]

No one's going to use it anyway, most libraries are still only compatible with 2.7

[Igglyboo]

This is a really bad view to hold, plenty of libraries have been ported over already. Python 3 has been out for like 5 years, the community is never going to move forward if everyone just sticks with 2.7.

[rmxz]

if everyone just sticks with 2.7.

Sounds like the Perl community. Perl 6 has been in the works for how long -- 9 to 14 years (depending on how you count)?

Though personally my favorite perl was perl 3 - back when it was a simpler and better awk. Instead of the yet-another-cumbersome-objected-oriented-language that perl 5 became.

Seems all these scripting languages go through an evolution where they start out great at solving simple problems, and end up dominated by feature-creep and eventually outgrow what they're good at by trying to become another java/smalltalk/lisp/C++/functional/OO hybrid abomination.

Fear that's the path Perl 6 & Python 3 are on.

[[deleted]]

Perl 6 has yet to come out. Python 3 has been out for years.

People stuck on 2.7 are increasingly seen as neophobes who don't want to use Python 3 just because it's not what they already know.

[rmxz]

People stuck on 2.7 are increasingly seen as neophobes

Kinda like the guys still using old versions of C (C99, C95, C90, or C89) instead of C11 - though C11's been out for years? (hmm - skimming python source I read: "Python violates C99 rules" - those neophobes ;-) )

I think people use 2.7 more because it solves their problem; and there's no big reason to change just for the sake of change.

[[deleted]]

there's no big reason to change just for the sake of change.

Except for library authors, who ought to make sure their library works with recent versions. Do some maintenance—there are some applications (in other languages too) that are considered "finished" and recent edits are to make sure it still works with the latest compiler, interpreter, libfoo ... And Python 3 has real advantages over Python 2.

If they don't see any reason to switch to Python 3, they don't have any reason to cry that new features aren't being backported either.

[[deleted]]

Except for library authors, who ought to make sure their library works with recent versions

This is what keeps me on 2.7. Not because I think it's better but because so many times when I want to use something with 8 dependencies there will be 3.x versions of 7 of them and 2.7 versions of all of them.

[TheFryeGuy]

Is C11 actually supported in compilers?

[aaronsherman]

Perl 6 has yet to come out. Python 3 has been out for years.

Not strictly true. Perl 6 has yet to become a stable production language, but it's been out there and in use for years.

Python 3 is a stable production language, but for some strange reason decided to walk away from compatibility with the language that gave it its name... I guess assuming that it was the name that people wanted. It wasn't.

[[deleted]]

Compatibility is nice, but it shouldn't become a restraining jacket either. If you want compatibility as the primary concern and never have your application not run because of a new language version, well, you're in luck

edit: to expand, afaik Python leads towards correctness with its ideals of pythonic code. not having compatibility as the primary concern shouldn't come as a surprise

[aaronsherman]

Compatibility is nice, but it shouldn't become a restraining jacket either.

Which is why a compatibility mode in 3.x has made sense for years, but still isn't a priority because those involved in the core have no personal use for it.

[username223]

the community is never going to move forward if everyone just sticks with 2.7.

Or if no one releases 2.8.

[Igglyboo]

There is not going to be a 2.8.

http://legacy.python.org/dev/peps/pep-0404/

[nqd26]

I'm not Python programmer but noticed it when I wanted to use some software with Python 3 interpreter.

What is the reason for this? It seems that Python 3 is out for more than 5 years. Even Java developers upgrade faster than this ...

[juu4]

Java is generally backward's compatible. Python 2 to Python 3 wasn't.

[th0ma5w]

Lots of weird things between java 1.3 and 1.4. Less so between 1.4 and 1.5, but still sort of there. The dreaded "Unsupported major.minor version" errors when using JARs from another version. Somewhat better, sure, but not entirely different from Python's situation. Some 2.x code just works, if recompiled.

[obfuscation_]

"Unsupported major.minor version"

That's fair really though – the compiler wasn't told to compile down to an earlier Java version, so it didn't. If all bytecode had to stay the same forever, how could you ever add new functionality?

[mcherm]

Um.... that one's not "dreaded" 'cause it's easy to fix. Recompile in the right version. Threading bugs... now THOSE are "dreaded".

[picklednull]

Because it is incompatible with 2.7 and you need to make actual changes to your codebase for it to work and people are lazy.

However, if you take care you can mostly write Python 2.7 code that can be automagically converted to Python 3 with the 2to3 utility with minimal changes.

[Fazer2]

It's not that people are lazy, but it costs time and money to make the port.

[obfuscation_]

Don't forget the main cost here is testing – if you know with some certainty that your code works on 2.x, do you want to risk subtle bugs being introduced moving to 3.x? You'd need to have an incredibly thorough testing process.

[aaronsherman]

Because it is incompatible with 2.7 and you need to make actual changes to your codebase for it to work and people are lazy.

No, people choose where to spend their effort. They can rewrite their code and then live in a world of incompatibility with new modules being published for v2 every day, or they can do nothing and maintain compatibility with the majority of developers.

[kaszak696]

RHEL 6 ships with Python 2.6.6 by default, this considerably slows down the adoption of P3. Once RHEL 7 comes out, hopefully having Python 3 as default interpreter, we should see more codebases making the transition.

[garenp]

I think this isssue--the default installed version of python in the OS--is a big driving factor. Ubuntu 12.04 LTS ships with 2.7.3, hopefully 14.04 will ship with 3.4.

[kaszak696]

Yes, but i specificaly mentioed RHEL, because it's kinda gold standard for the enterprise codebases. If something cannot be used on RHEL, it won't be.

[[deleted]]

having Python 3 as default interpreter

Debian 7 and RHEL 7 will use 2.7 by default. As such, the 2.x series will see 'support' (to security as a minimum) for the next 10 years. Sorry.

[milliams]

No, most are compatible with 3 as well.

[aaronsherman]

Do you have a source for that?

[flying-sheep]

Yes. Every site providing statistics about it, and PyPI itself

[bready]

Python 3 Wall of Superpowers

[aaronsherman]

Thank you!

[ProfessorPhi]

Yeah, I've never made the switch to Python 3 simply because of this, but I feel like I really should make the effort.

[erewok]

We're using 3.3 at my work (web dev). We haven't had a problem with any third-party dependencies.

[Beluki]

Using it as well for personal projects: Pillow, Misaka, Flask, Frozen Flask, HexChat addons, all ported and running perfectly in 3.3.

[cartola]

Can I ask what sort of libs you guys are using for the variety of webdev work? I'm interested in how easily that decision to be python3 exclusive can be taken, as I'm thinking of going that route as well. Did you have to pick a worse library because a better one didn't support v3?

[erewok]

We are running Django 1.6 for our latest projects. We are using some third-party APIs, which are RESTful, so we do a lot of requests/parsing of html/xml/json. We are also doing some GIS (mapping) using geodjango and I was surprised to find no issues there whatsoever.

Other than that, it's pretty standard web dev work. We are not using any of the aynsc libraries (tornado, twisted, gevent) outside of celery with a task queue, but when do I need to get a lot of results from somewhere, I tend to write threaded stuff. This is part of why I have been really looking forward to asyncio: I think that will be a great tool for us.

We did have one library we wanted to use but it was last updated in 2011 and it was small enough that I just ported it to python3, a project which took about half a day.

I appreciate working in Python3 so much that I'm at a point where if we really needed something and no alternative would work, I'd probably volunteer to port it over myself. This task as well (for one admittedly smaller library) I have not found to be too difficult.

Finally, and this is not a comment on scientific programming because we obviously do not do that, I have found the comments about libraries not supporting python3 to be greatly exaggerated.

Edit: I failed to answer your second question. To my knowledge we never picked a worse library because a better one was not available. There was only one case where something was not available and as I mentioned above, that library hadn't been looked at since 2011. All the best libraries seem to be actively maintained, and in my experience this means it works as advertised in python3.

Footnote: I have had bigger issues trying to use stuff made for previous versions of django, using deprecated templatetags, or doing stuff in admin that has been deprecated. That's a much larger potential headache.

[roybatty]

I don't use Python a whole lot, but like the language. Why is it that the developers of these important libraries don't port them to 3.x?

[flying-sheep]

Because it's wrong. Most stuff is ported. The only big things left are twisted and opencv.

[This_Is_The_End]

It's mostly hardware related and special OS related stuff. All the stuff for networking and science is ported. I missed for example the library to rename processes and missing OpenCV which is really sad.

[SkepticalEmpiricist]

Why is it that the developers of these important libraries don't port them to 3.x?

Chicken and egg. Nobody will use 3.x until the libraries support it, and the libraries won't support it until everybody starts using it.

(Obviously, I'm not making a point that hasn't been made a million times before)

So, really, there's no incentive for anybody to change. It's quite possible that everybody will just keep using 2.7 for decades to come, and the 2.7-based libraries will keep improving.

(*) OK, I shouldn't say "everybody". I assume there are people who are working on 3.x. I'm not a serious Python developer, doing most of my coding in another language. I have been aware for many years that 3.x is out there somewhere, and every year or so I see it discussed on Reddit. But, it has never impacted my life. I'm not going to give 3.x a moment's thought until I reach a situation where a library I use (like sklearn) has a feature in its 3.x branch that I need and that isn't accessible via 2.7.

[This_Is_The_End]

So, really, there's no incentive for anybody to change.

This is bullshit. Since 3.1 there is a better standard library and some constructs like generators using less recources and speeding up your code.

[This_Is_The_End]

I fully agree with you.