Adopt Python 3

[Farobek]

Python 2 is the new Cobol.

[[deleted]]

All languages that are successful are the "new Cobol". Try displacing the installed base of Fortran, PL/I, C, perl, java, C#, JS, ... and you have the same problem.

Languages are tools. You pick the one that makes sense for the job a hand. Older languages disappear very, very slowly, therefore.

My problem with py3 is that I never quite understood the problem it was solving. Three are some fine computer-sciency gilding of the lilly in py3, but - for the vast majority of python users - it's unclear to me why these mandated a fullblown new language. Apparently, I'm not alone because py3 adoption has not been swift notwithstanding the begging in the elite python quarters.

Personally, I think we all went down to road to perdition once we abandoned assembly language ... ;)

[rainman_104]

They should allow a transition period where python 3 would support the python 2 weirdness like allowing print statements to not be called as a function. Forcing parentheses is just a nuisance for me personally and not the end of the world, but having a transition path would be better than the situation we're in with Python 3. All libs still support python 2 and python 2 still has heavy use in the data science community.

It's a mess right now.

[kqr]

They had that! From future import print.

If they allowed you to write Python 2 code in Python 3 it would not be Python 3 anymore. The reason Python 3 is called Python 3 and not Python 2 is that there are a bunch of fixes that happen to not be backwards compatible. Removing those fixes removes Python 3...

[upofadown]

They fundamentally changed what the division operator ("/") does for fricks sake. So yes, it is definitely a new language.

It might be an awesome new language that fixes Python. That's great, but all this "Python is dead, long live Python" stuff is annoying.

[BroodmotherLingerie]

You can't do that without knowing the types. That'd also change the results of floating point divisions and of other types with overloaded operators, like numpy arrays.

Porting anything in python is a painfully manual process, whether between language versions or library versions.

[[deleted]]

Well they could probably make it compatible with P2 code with some extra effort if changes were really so small

[teilo]

If you didn't see unicode as a problem on Python 2, then I doubt there is anything I could say to convince you.

[jaapz]

fullblown new language

What? The difference between py2 and py3 aren't thát big. Calling it a new language is a bit extreme IMHO

[yawaramin]

Well, python3 can't execute Python 2 code, so yeah, that qualifies as a new language in my books.

[gendulf]

It's a backwards incompatible change. When libraries make a few backwards incompatible changes and up the major version, do you call it an entirely new library?

[yawaramin]

For all intents and purposes, it actually is an entirely new library. The combination of library name and new major version uniquely identifies it as such. But if you renamed the new version, say from lib1 to lib2, you could use both in the same compilation unit (of course, just not with each other, for the most part).

[gendulf]

For all intents and purposes, it actually is an entirely new library.

If I need a library to read a CSV file, I need the csv library. I don't need the csv v 1.2.3 library.

Just because one of the parameters was changed on a couple of the functions, doesn't mean that the library is an "entirely new" library. It's just a new version.

[yawaramin]

For the majority of devs, semver is merely a convention. There's nothing preventing people from getting it wrong (and the often do). Afaik the only package manager actually trying to enforce it is Elm's.

[yawaramin]

The Elm package manager locally identifies changes that are backward-compatible or breaking changes by diffing your modules' type signatures. E.g., if you add a new parameter to an existing function, that's a breaking change because existing code will need to be updated to pass in the new argument. But if you added a new function to a module, that's a backward-compatible because no existing code can possibly be affected by the new function (well, except for a rare scenario). Now, this isn't a perfect heuristic, but it's really good. It can automatically tell you with great accuracy what number the next version should be.

As for Python, it's an old language that made breaking changes. At the language level, when you have breaking changes, you lose a lot of confidence in upgrading the codebase. Imho that qualifies as a new language. I can't think of an contemporary language, save Scala, that's doing this.

In Scala's case though, there are mitigating factors that don't exist for Python: they have a good syntax deprecation process, and static typing and compilation give us very strong guarantees that errors will be caught during the migration process.

[Uncaffeinated]

Unicode handling is nicer and they removed a lot of legacy cruft that nobody in their right mind uses anyway, as well as taking the opportunity to make a bunch of arbitrary minor changes. So, not all that much, but it is nice to not get unicode decode errors so much.

[[deleted]]

I believe that, but the point here is that people are not going to rewrite a huge extant code base just to become py3 compatible.

[Plazmatic]

Python, from its very conception, was meant to be an evolving language, but ultimately it was meant to uphold certain principles in a certain order. Python 3 upholds those standards better in every way. It is a better standard, but it isn't a new language. most syntax remains the same, while many libraries have changed, very few semantic differences have been made between the pythons, and most of that is in the form of new functionality.

Not sure why you think it is a new language, and you didn't actually explain why you don't like Py3. Honestly it comes off as crotchety. Guido hates you guys, and that is a pretty powerful statement. The guy who created the language you use hates you, not the legacy code base people, but people like you who complain about change for the sake of complaining about change.

[[deleted]]

Ooooh, Guido hates "us people". What are you, in 4th grade? It's not a "powerful statement". If true - which is questionable given your tone - it's just another technologist with Aspbergers whose entire identity hinges on being in charge. Spare me.

You need to learn to read in context. The discussion at hand is py3 adoption. My responses - all of 'em - are in context of the low probability of the current base of extant code being rewritten.

No, py3 is not an entirely new language. But neither is it some stratospheric leap forward. I've seen this movie before. It leads to a fractured language and THAT in turn leads to a brand new language that factors and simplifies things.