On which interpreter is used, you can control this with (IIRC) something
like
port select --set python3 python3.6
port select --set python2 python2.7
port select --set python python2
# or "port select --set python python3" if you like
It's most flexible to say #!/usr/bin/env python2 or #!/usr/bin/env
python3 in scripts (rather than, say, #!/opt/local/bin/python or
#!/usr/bin/env python), as this ensures the right major version, and
will use an enabled virtualenv's copy of the interpreter.
#!/opt/local/bin/python3 would work too.
Don't forget there's also /usr/bin/python and /usr/bin/python2.7. These
are best avoided.
The Apple-provided build of Python is installed in
/System/Library/Frameworks/Python.framework and /usr/bin/python,
respectively. You should never modify or delete these, as they are
Apple-controlled and are used by Apple- or third-party software.
Remember that if you choose to install a newer Python version from
python.org, you will have two different but functional Python
installations on your computer, so it will be important that your
paths and usages are consistent with what you want to do.
https://docs.python.org/2/using/mac.html
Russell
On 27/04/17 14:38, Russell Jones wrote:
In short, most stuff works with 2 and 3, and you should use 3. You can
install both, they're independent. virtualenvs are your friend. Also,
"import this" if you haven't already :)
In full, it's quite complex. See
https://wiki.python.org/moin/Python2orPython3
For most features and least hassle, use 3 and ignore 2 if you can. If
you have old 2 code of your own, have a look at http://python-future.org/
Stuff being 2 only is a bit of a red flag. It's likely unmaintained or
has architectural or testing problems such that it can't be ported.
Some newer stuff is 3 only-- typically to rely on new 3 only features
like asyncio. 2 and 3 stuff is so because of some effort by the
developers to make it so.
Russell
On 26/04/17 20:59, Michael wrote:
What is involved in switching from python 27 to python 36?
I've been using python 27 for a while. I've run into a problem with
youtube-dl needing a newer python.
But I don't know what I need to do to safely update. It's not like
python2 is a different program than python3 (same "python" in both
cases), and as I understand it, not everything written for P2 is
compatible with P3.
So what's the proper way to upgrade?
Or is there a way to have both installed at the same time? (but then
... !#/usr/bin/env python ...)
---
Entertaining minecraft videos
http://YouTube.com/keybounce
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