Python 3 - Safe to use/convert to?

[ahi]

Anybody trying to do work/convert their scripts to Python 3?

Any verdicts, problems, pitfalls you could share with the rest of us?

- Ahi

[JSWolf]

Python 3 has changed enough so it's not backwards/forwards compatible. All the scripts used to remove DRm won't work with Python 3 and anything you code with Python 3 most likely won't work with 2.5.x or 2.6.x. So basically it's a botch job (IMHO) due to compatibility issues.

[ahi]

Originally Posted by JSWolf

Python 3 has changed enough so it's not backwards/forwards compatible. All the scripts used to remove DRm won't work with Python 3 and anything you code with Python 3 most likely won't work with 2.5.x or 2.6.x. So basically it's a botch job (IMHO) due to compatibility issues.

I was aware of the purposeful breaking of backwards/forwards compatibility. My question was more aimed at finding out whether people found it difficult to port their Python 2 scripts over to Python 3 and/or whether they found Python 3 easier or harder to program in.

When dealing with Unicode text, I get the impression it ought to be a bit more straightforward... but I fear pitfalls in this still rather young release.

Further clarification: I meant "convert to" in the sense of "converting scripts to", not in the sense of "switching your primary Python installation to". I rather agree with JSWolf that doing so would probably be foolhardy at this time... unless concurrent installations are possible, with Python 2 remaining the default.

- Ahi

[JSWolf]

I don't think Python 3 will take off unless they can fix it so it also runs 2.5.x/2.6.x code without any modification.

[kovidgoyal]

Python 3 is significantly slower because of it representing all string internally as ucs 2 or 4

Most 3rd party modules haven't been ported/have bugs with python 3

Note that using __future__ you can write code that will run correctly on both 2.6+ and 3.0. For new projects that's what I would recommend

[ahi]

Originally Posted by JSWolf

I don't think Python 3 will take off unless they can fix it so it also runs 2.5.x/2.6.x code without any modification.

I suspect there is no chance at all of any solution that literally has Python 3 providing compatibility.

Though, to be frank, I suspect that for those with a bit of system administration knowledge (like the Ubuntu maintainers, web hosts, et al) running both Python 2 and Python 3 concurrently is probably trivial. Hence I'm not convinced this is actually a problem.

Here's a list of changes/conversion notes for Python 3. My interest is piqued.

- Ahi

[kovidgoyal]

I have python 2.4, 2.5, 2.6 and 3.1 on my machine

[ahi]

Originally Posted by kovidgoyal

Python 3 is significantly slower because of it representing all string internally as ucs 2 or 4

Most 3rd party modules haven't been ported/have bugs with python 3

Note that using __future__ you can write code that will run correctly on both 2.6+ and 3.0. For new projects that's what I would recommend

I have some Python code that works Extension Plane B CJK characters that aren't correctly handled by Python even as UTF-8... if Python 3 can recognize them and work with them cleanly, I shall be happy.

But I will check out __future__. Portability would still be nice. I'm guess though it is far from effortless.

Originally Posted by kovidgoyal

I have python 2.4, 2.5, 2.6 and 3.1 on my machine

Was it problematic to set them up?

- Ahi

[kovidgoyal]

Yeah, you have to know what you're doing to use __future__ correctly.

I use gentoo, a source based linux distro, which actually sets up the multiple python instances automatically for me

[ahi]

Originally Posted by kovidgoyal

Yeah, you have to know what you're doing to use __future__ correctly.

I use gentoo, a source based linux distro, which actually sets up the multiple python instances automatically for me

Ah, yes... I left Gentoo behind around the birth of my second daughter.

I now settle for whatever Ubuntu maintainers think up for me... with only the occasional attempts to try to do the inconvenient thing they did not think of doing.

- Ahi

[kovidgoyal]

Python is designed to work well with multiple instances, so it shouldn't be hard to do.

Basically, just compile it from source and install into different prefixes, then setup appropriate symlinks pointing to the different versions in /usr/local/bin or wherever

And make sure you dont have any PYTHON* environment variables