Can I Use Python 3? (opens in new tab)

You know, when I am working on an existing project for a client that's allotted 15 hours a week to it, and I have to get actual features pushed out, I don't have time to check which of the 25+ dependencies I list are going to work in Python 3. Sure, maybe I can start a new project in Python 3, but there are enough existing projects to not be able to do this.

Also, even if I am starting an existing project, what if down the line I must use a library that's only available for Python 2? I am not going to rewrite something like that because it will cost my client money if I spend time on it.

The problem with Python 2 is that it's good enough. Python 3 is a huge improvement, yet until I can be reasonably sure that all libraries I am likely to use are available for both, Python 2 is the winner.

Having said that, any personal projects I have started recently have all used Python 3 and it's been great. I also try to make sure that any libraries I write work in both.

There is no such thing as a legacy programming language. Python 2 and Python 3 are two different, incompatible programming languages. The existence of Python 3 doesn't make Python 2 code legacy code.

Its not always the developer.

For instance, I do some utility class software that needs to just work on RedHat/CentOS 6. Having to build Python 3 from source, or use SCL and mess with paths, and virtualenvs is simply not an option for my target user.

> It's kind of disappointing that developers aren't self-aware enough to understand that they are essentially screwing themselves by not moving quickly in dropping "legacy" support.

I think the part that might be missing from your line of reasoning is context: For professionals and entrepreneurs programming isn't a hobby, it's a business.

The decision to stay with 2.x isn't about not being self-aware. It's about being serious about your business. Business has nothing to do with self-awareness. It would be irresponsible to send your organization down a path that could result in a huge setback.

If you are self-funded this could absolutely kill you. If you are in a competitive environment where time to market is crucial (who isn't) this could kill you. If you have investors who expect you to make responsible decisions, they could kill you.

How are you going to explain the decision to go to 3.x when the fertilizer hits the ventilator and you realize there are three choices in front of you:

    1- Redo your entire codebase to migrate down to 2.x.
    2- Launch a new project to rewrite the 2.x libraries you need.
       This could take one week or one year.
    3- Shut it down because you don't have enough cash to deal 
       with having made the wrong decision.

And, here's the kicker: You won't know until you hit that wall. Sure, you can do an initial dependencies survey. And hope you went deep enough. By definition, you will have no way to check dependencies you don't know about at the start of the project.

The bottom line is that in the context of a real business --not a hobby-- sticking with 2.x is probably the only responsible choice for a huge number of organizations. I really think the Python leaders made a mistake in not coming up with a smooth on-ramp onto the various ideas in 3.x. I do understand that some things need to be broken sometimes. In the real world you can only break so much of a codebase before people avoid it like the plague.

Here's the other reality: The customer doesn't give a damn whether you are using 2.x, 3.x, Python, Lisp, PHP or assembler. They buy your product or use your service because of the value they derive from it. For the vast majority of businesses and customers this has nothing whatsoever to do with the technology choices you make behind the scenes. If this fact isn't obvious, study the history of a number of prominent startups and you'll find support for this idea.

It's easy to fall back on engineering think and forget reality. I do it all the time. Over the years I've become better at avoiding thinking like that. Like wanting to build a product without doing market research and, a year later, finding out the hard way nobody wants it.

I'm not criticizing you here. I am simply pointing out something we all do from time to time.

Who exactly am I screwing by sticking with python 2? It's certainly not me or my employers.

Maybe if van Rossum had produced a compelling reason to switch (like, for example, removing the GIL) I would have gone over by now.

I'm willing to be the vast majority of Python code in existence right now is academic in nature.

Most academics--from an engineering standpoint, mind!--write really shitty and garbage code, under deadline to submit yet another paper for the mill.

There is no surprise that they would be unable/unwilling to appreciate the long-term damage they inflict on themselves when using what should be deprecated features.

Meanwhile, Rubyists and Node rockstars are laughing all the way to the bank, and the Erlang bros are already there.

EDIT:

Okay, fine, downvote, but at least mention which part of that statement you disagree with.

Flask: you can, but you really shouldn't, at least not for anything you plan to deploy.

http://flask.pocoo.org/docs/python3/#python3-support

http://lucumr.pocoo.org/2014/1/5/unicode-in-2-and-3/

Which kind of sums up the whole Python 3 situation.

We've been working with the Oracle connector for MySQL [1] without any problems.

[1] https://dev.mysql.com/downloads/connector/python/

There's also oursql, which isn't API compatible with MySQL-db, but is generally better (and works fine, in my experience).

No, distributions are way behind

2to3 is bad and the code involved has to be tested using it anyway.

The normal way to install Python packages is not by manually downloading them

> You can then download that, and use something like 2to3 to convert it.

Only in some cases. Pretty much anything that handles binary formats on the wire will need some tweaking.

No, because the packages provided by your distribution are a subset of all the python3 packages available.

PHP4->PHP5 was a big breaking change as well. It took several years for all projects nad hosting companies to upgrade and switch to v5 by default.

But there was a strong push from developers. I don't see that happening when Python developers' attitude is "Meh, Python 2 is all right, I don't need to upgrade anything ever".

Lots of apps die in the wake of the new.

Pyglet and Pygame both support Python 3.

PyGame also claims Python3 support for several releases back. I agree on the installation part though. Pyglet is really the one I've found easiest to install and get started with.

How very recently was this? The pyglet dev version from 2012 at least claims to be for Python3.

This is actually what you want http://py3readiness.org - site that uses `caniusepython3` and shows support graph for popular packages.

This is a list containing some of the more popular python libraries: http://python3wos.appspot.com/

aside: I was secretly hoping it only supported python2.

Thanks for that though. It will be much more useful with requirements files.

By your advice, the bad unicode situation in Python 2 would never have been fixed.

That's not a bad thing, though. That signifies ambiguity in your code. You're better off fixing problems like that than you are letting them go undetected or unfixed.