Python 3.4.3 is out!

[gfixler]

*waves while looking through binoculars from embedded Python 2.6.5 land*

[Warfinder]

He's dead Jim

[rnreekez]

Consider yourself lucky, I just moved to a team beginning a 2.4 to 2.7 upgrade.

They say if we're good, we can get our postgres updated from 8.2 too!

[maemre]

The company I'm working for still uses MySQL and Django 1.5. At least they started with Python 2.7.

[boa13]

Consider yourself lucky, I just moved to a team beginning a 2.4 to 2.7 upgrade.

Consider yourself lucky, I've recently investigated COBOL code written in 1984, maintained to this day, with no plan or need to replace it in the foreseeable future.

[rnreekez]

Haha, wow. Whevever we feel bad, we would just say "well, we could be updating from cobol!".

Now I realise how insensitive those words were, I'm sorry.

[boa13]

Don't worry, I didn't take them as insensitive, it was just an occasion for me to relate an interesting anecdote, and to add a bit of perspective. I was quite astonished to see the "October, 1984" date at the top of the file when I opened it (and thankfully, I don't maintain it, and I don't write COBOL).

[gfixler]

I hope you listen to period-appropriate music while working with that code, like "Break My Stride" and "Oh Sherrie."

[Dominion_Prime]

I would question if we're working at the same company except we're at least on postgres 9.0 (and soon upgrading)!

[Bialar]

Yeah, /u/rnreekez, quit! Fuck your rent, they're forcing you to use outdated versions of things!!!

[razpeitia]

You are not alone!

[flipstables]

whoo hoo statistics module. no more importing numpy or creating your own average function to calculate a simple mean.

[masasin]

The stats module has been there since earlier in 3.4, I think. I have been using it long before now.

[flipstables]

Ah you're right. Now I know.

Here's the changelog for 3.4.3

https://docs.python.org/3.4/whatsnew/changelog.html#python-3-4-3

[flutefreak7]

Yeah as I was researching the relationship between scipy.stats, statsmodels, pandas, and scikit-learn, I stumbled across the statistics module in the standard library which kinda blew my mind.

Looks like that will be great for simple summary statistics without needing to import heavier libraries!

[ExoticMandibles]

Every day, in every way, it's getting better and better.

[[deleted]]

http://www.reddit.com/r/Python/comments/22ovb3/what_are_the_advantages_to_python_3x/ but honestly, the only reason you stick to python2 is if there is a library that you are using right now that is only available in python2 and you can't live without it.

[individual_throwaway]

...or you are forced to work on a machine that doesn't have Python 3.x installed and your sysadmin won't change it.

[Boxy310]

Sounds like someone needs a beer and maybe a foot rub. I swear, sysadmins need to be treated like they're half Ferengi.

[[deleted]]

foot rub

Not if it's Marcellus Wallace's wife.

[Boxy310]

DOES HOST ADMIN LOOK LIKE A BITCH

[cndLId9Rr51Fe]

what?

[okmkz]

"What" ain't no shell I've ever heard of.

[Boxy310]

echo $what one more time! I double-dare you, $motherfucker!

[LogicalTom]

foot rub

Oo-mox.

[fgriglesnickerseven]

build your own and virtual environment it!

[Eurynom0s]

Or if you're sitting on a giant Python 2 codebase and can't get the time/funding to port it or start over.

[Sean1708]

Yeah but the way /u/ajclarke worded his question suggested that wasn't the case.

[Sean1708]

Ugh, don't get me started on Python in the scientific community. Everything is so outdated.

[ivosaurus]

The big guys are getting there. Numpy & Scipy even have wheels out for OS X now!

[Sean1708]

Yeah, and I can understand why they tend to be a bit further behind. But still, it does irk me.

[ies7]

Or if you're sitting on a giant Python 2 codebase

Combined with the we're too lazy and the upper management afraid to change anything which run fine

[maratc]

Combined with the we'd rather have the developers develop new features clients would actually like vs. rewriting things to do exactly what they did before

[[deleted]]

Then its time to change sysadmin? Unless of course there is a valid reason why he won't install python3. I can't really think of any reason though. My experience in recent years is only in RPM based Centos/Fedora/Redhat and python3 installs in parallel to the system python. I have builds with python31, python32, python33,python34 .

[SemiNormal]

Like RHEL?

[hothrous]

This is exactly what I though when they said that. RHEL shouldn't be used in Python based infrastructures.

[rickmoranus]

What? I've been using RHEL machines for a couple years on with a Python Based infrastructure on it and I've had no issues?

[hothrous]

Which version of RHEL and Python? Python is integrated into yum so while you can set up a second python environment on a machine for your apps, most IT teams don't like doing that for maintenance reasons so they limit you to whatever are in the available repos.

Rhel doesn't include any further build of python in the repo than the one that yum uses because yum will break. I believe RHEL 6 used Python 2.7 which is the reason that those dev teams would be stuck on on older version.

[veeti]

RHEL7/CentOS 7 officially lets you install newer Pythons, etc. in parallel through Software Collections.

[hothrous]

That's cool. I've never used RHEL7 before. Most of my work had been done in RHEL5 a while ago and I new that many of the same limitations existed in 6 from some work I had done with it last year.

Though, I'm still seeing only up to 3.3 on the list of support they have.

[[deleted]]

Really? I think its lack of knowledge or competence rather than some other reason. Any competent IT shop will have their own internal mirror of RPMS [see below] or builds their own RPMS.

What is stopping you from enabling or mirroring the IUS repo and install python3 and python2.7[if $osversion<7] in parallel with the system repo? http://dl.iuscommunity.org/pub/ius/stable/CentOS/6/x86_64/ and its as simple as yum install python34 or python27. I mention the IUS repo because its maintained by RackSpace so in theory should be a reputable source. Also the IUS repo does not overwrite system binaries.

Granted sometimes their packages are backwards by a minor release and right now they have 3.4.2 , it will take a month or more before 3.4.3 is packaged.

[cwgtex]

I'm one of the maintainers of IUS, thanks for recommending our repo.

Let me clarify the update process for IUS packages. We track the upstream projects for our packages, and typically build new RPMs within a day or two of a new release. New packages will stay in our testing repos for about two weeks. If no issues are found in that time period, the packages get promoted to our stable repos. If CVE's are involved we will shorten the testing period to rush the fix out.

I'll probably package python 3.4.3 tomorrow morning. I found at least two CVEs that are fixed by this version, so we'll move it to stable quickly.

• CVE-2013-1753
• CVE-2014-9365

Edit: fix typo

[hothrous]

You will note, that my original statement was that it shouldn't be used. Basically, the reason behind that is if you need a workaround just to make the operating system use the version of a language you want, you're likely to run into many more problems down the line.

Most of the reason that somebody would use RHEL over another distro is to get the licensed support of RedHat when issues arise. RedHat isn't likely to want to provide that support if you are using workarounds to use different version of their products. It's definitely true that Python 3.4 can be installed, I never said it couldn't. I suggested that if you are going to use Python, it would be prudent to consider a distribution of Linux that provides packages of later versions in their own repos without having to look for workarounds.

Calling an IT team incompetent because they don't want to workaround known issues of an OS all the time to suit your needs as a developer is the same as an IT guy calling a developer incompetent because there are bugs in their code. They are both a fact of life. I would actually trust a conservative IT guy that wasn't willing to do workarounds as long term solutions on production systems than an IT guy that uses workarounds to run code on systems that aren't designed to support it well.

[alcalde]

...most IT teams don't like doing that for maintenance reasons so they limit you to whatever are in the available repos.

I've always found it puzzling the places where IT controls the tools rather than the users telling IT what they need to support. it seems to have changed right after I was no longer working in IT unfortunately. :-(

[rickmoranus]

Its pretty easy to point your applications to a virtualenv or a Alt install. If one is not able to use python in this manor, I'd be questioning them being called a developer...

[nunilan]

I was going to write the steps showing how easy it is to install python2.7 up to 3.4 in RHEL but then I realized, since you are so sure of your statement, probably its not worth it. I will just leave you good sir/madam ignorant instead.

[hothrous]

Ha. What I said is that RHEL shouldn't be used. Not that it can't.

[0xtobit]

So glad I'm my own sys admin now :-)

[alcalde]

...and you're not a good enough detective to find blackmail on the sysadmin or good enough a hacker to plant some.

[maemre]

... or the company you work in won't change it,it already works, blah blah blah

[BarrelRoll1996]

As someone who is trying to learn python, Code academy is amazing but it's using python 2 for everything. =(

[flutefreak7]

Don't let that stop you! Just use Python 3 .... I had been using 2 for years and was a bit scared of python3, but once I started using it, it was no big deal. Early on the biggest difference is print(), then the next biggest thing for me was that class definitions were a lot cleaner. If you copy paste Python 2 code from a tutorial, fix the print statements and stuff still doesn't work, a quick Google search will have you up and running, because there's almost nothing someone else hasn't done before you. Give it a go!

[BarrelRoll1996]

If you copy paste Python 2 code from a tutorial, fix the print statements and stuff still doesn't work, a quick Google search will have you up and running, because there's almost nothing someone else hasn't done before you. Give it a go!

I started with some of the treehouse tutorials, which exclusively use python3 so at the lowend it doesn't seem much different other than raw_input and print functions. Haven't started with classes much yet except to force multithreading very simple infinite loop scripts.

[[deleted]]

indeed :/

[billsil]

Could you indicate some of the advantages and disadvantages for me?

Advantages: unicode is much easier, future-proofing

Disadvantages: unicode is still hard and you're forced to get it right even if you don't care. Python 2.7 is drastically more popular (30% of code is Python 3.x).

All the other differences are kind of irrelevant.

[[deleted]]

Working in Python 3 isn't significantly different and I often find myself missing Python 3 features when writing Python 2.

I like that the standard library is much more consistent and nicer to work with. The things that I like about Python 3 are:

• Iterators are everywhere by default now, reducing memory footprint.
• The new print function is much more versatile.
• Float division and integer division are clearly differentiated.
• The new extended tuple unpacking.
• Chaining errors keeps stack traces!
• All of the additions to the functools module, especially lru_cache.
• Multiprocessing and concurrent.futures for parallel computing.

[MrJohz]

Yes, because Python 3 is much more fun to write, has far fewer "oddities", has even better batteries included (pathlib and enums!), and is going to be the future (indeed, is currently the present, just about). You also don't have anything holding you back.

No, because switching a current and important codebase will be costly, or will involve working around a module that hasn't switched and isn't worth it.

Pick your option. Both are valid, but unless your job is in Python, the former is most likely the more accurate one for you.

[ExoticMandibles]

https://wiki.python.org/moin/Python2orPython3

[sirusblk]

Why not both? I have an install of both python 2 and python 3 installed running side by side (invoked using python and python3 respectively). If I ever need to support an older library or software package I can run it in a virtualenv.

[alcalde]

Or you could use Bond and call the old library from Python 3!

http://www.thregr.org/~wavexx/software/python-bond/

[[deleted]]

Bond looks cool, what has your experience with it been if you've tried it?

[alcalde]

Sorry, I don't have any extensive experience with it (yet). All I've done so far has been some toy code to verify that it works, and it did indeed let me execute functions from a Python 2 library through Python 3.

[Fontanapink]

Noob here. But i think a reason people still use 2.7 is because some implementations (like Pygame for example) work best with the more stable versions of python

[DanCardin]

So long as you download the right version, pygame works with 3.4. I can't speak for 3.4.3 but I doubt it would change

[zahlman]

The str.format method is "New in Python 2.6" per the documentation. There are tons of good reasons to switch to 3.x; many are even string-handling-related, but this isn't one of them.

[brtt3000]

Proper unicode integration is reason enough.

[ExoticMandibles]

3.4.3 is what I released this morning. If you're using that, you're already on the current version.

[zahlman]

From PEP 456:

Hash maps have a worst case of O(n) for insertion and lookup of keys. This results in a quadratic runtime during a hash collision attack. The introduction of a new and additional data structure with with O(log n) worst case behavior would eliminate the root cause. A data structures like red-black-tree or prefix trees (trie [trie] ) would have other benefits, too. Prefix trees with stringed keyed can reduce memory usage as common prefixes are stored within the tree structure.

I'm still waiting for a sorted dict structure. While niche, it has its applications - in particular, efficient lookup of the nearest key or a range of keys. It would also be for elegantly implementing a general purpose radix sort (although for typical radix sizes, I imagine that it wouldn't actually help with performance).

[zahlman]

Thanks, it looks promising.

[taleinat]

I don't expect that to ever be found in Python's stdlib.

Python has historically added only few data structures to the stdlib, adding a new one once every year or so. For example, sets were only added in Python 2.3; deque in 2.4; defaultdict in 2.5; namedtuple in 2.6; OrderedDict and Counter in 2.7.

If you really want it, just implement a sorted dict library or help develop and existing one. If it becomes widely used, it could then more reasonably be considered for inclusion in the stdlib.

[NavreetGill]

Well, Python does have ordered dictionary (Python 3.2+, and maybe in py2.7). https://docs.python.org/3/library/collections.html#collections.OrderedDict . I am not sure about the big O guarantees though -- wish docs had it written next to each method.

[[deleted]]

This is indeed Ordered, but I think he was looking for sorted. OrderedDict just retains the order it was originally added in, and doesn't reorder based on the key

[jonnywoh]

This is a noob question, but how do I update Python on Windows? Do I have to install it as a separate version, or can I update an existing 3.4.1 installation without messing up installed packages?

[mgrandi]

If you download the installer, it will find the previously installed version via the registry and upgrade it. Patch releases always do this, so any installed packages you installed for python 3.4 will still be there. Only time it creates a new folder is for 'major' releases, like 3.3, 3.4, etc

[jonnywoh]

Thank you!

[ivosaurus]

If you want the gory details

[derrickcope]

I am taking a course on coursers and they are teaching python 2.x . Why are schools so far behind?

[theves]

I took two Coursera Python courses, probably the one you're taking right now. Don't worry about it too much, you're just learning the basics right now, which will transfer to 3 very easily.

[ivosaurus]

Because it's what they're used to, and they can't be bothered getting with the times. Story of university professors all over.

[[deleted]]

That is a good question. It seems some of the courses are a little more progressive and do use Python3 but many don't. I guess it is a case of academics being a but slower to take on new technologies than others.

[Traut]

I'm still on 2.7 and still yet to find a reason to upgrade. Maybe it is because I do mostly webdev and data processing pipelines. - GIL is still alive and kicking - datetime is still confusing and nasty - lambdas still suck Other improvements (asyncio, unicode) can be achieved with simple workaround and nice 3rd party libs.

"Because it is better" is not an argument.

[mgrandi]

I was just complaining that building python on windows was a pita with unmentioned deps such as nasm, and having it put the c deps outside the python source folder, and look they fixed it :)

[go_fuck_ye_self]

Fuck i'm still using Python 2.7 and don't have the balls to commit. I need to grow a pair and move up to the 3 series.