Can I have both Python 2.7 and Python 3.1 at the same time on the Mac?

[Jason Swails]

MacPorts!  They include a nifty little package called python_select that
lets you switch default python versions on-the-fly and organizes everything
for you perfectly.  I have python 2.4, 2.5, 2.6, 2.7, 3.2, and the system
default 2.6.1 all installed, and

python_select python27
python_select python32
python_select python26-apple

switches seamlessly between them.  (I have so many versions to test script
compatibility, not because I'm an avid collector).  In any case, this seems
to be an ideal solution.

All the best,
Jason

On Thu, Jan 6, 2011 at 5:25 PM, Bill Felton
<subscriptions at cagttraining.com>wrote:

> On Jan 6, 2011, at 3:46 PM, Ned Deily wrote:
>
> In article <775A9D45-25B5-4A16-9FE5-6217FD67F3AF at cagttraining.com>,
>
> Bill Felton <subscriptions at cagttraining.com> wrote:
>
> I'm new to python, trying to learn it from a variety of resources,
> including
>
> references posted recently to this list.
>
> I'm going through /www.openbookproject.net/thinkCSpy/ and find it makes
> use
>
> of gasp, which apparently is not compatible with 3.1.
>
> I've also seen various resources indicate that one can install both Python
>
> 2.7 and Python 3.1 -- but when I did this, I get no end of problems in the
>
> 2.7 install.  IDLE, in particular, fails rather spectacularly, even if I
>
> launch it directly from the Python 2.7 directory in which it resides.
>
> So, either I've been misled and should only try to have one or the other.
>  OR
>
> I'm missing some (probably simple) step that's mucking me up.
>
> Help?
>
>
> Yes, you can have multiple versions of Python installed on Mac OS X.  In
>
> fact, Apple ships multiple versions of Python with OS X (2.6 and 2.6
>
> with OS X 10.6, for example).  Starting with Python 2.7, python.org
>
> offers two variants of OS X installers, one is 32-bit-only and works on
>
> all versions of OS X 10.3.9 through OS X 10.6, the other supports 64-bit
>
> execution and only works on 10.6 (as of 2.7.1).  Unfortunately, there
>
> are some major interaction problems between Tkinter, Python's GUI
>
> toolkit which is used by IDLE, and the Tcl/Tk 8.5 supplied by Apple in
>
> OS X 10.6.  I'm assuming you installed the 64-bit version.  If so, until
>
> the problem is resolved in the next maintenance release of Python 2.7, I
>
> suggest you download and install the 32-bit-only version of Python 2.7.1
>
> which does not have those problems.
>
>
>
> Thank you, Ned!  Installing what appeared to be the 'old OS' version seems
> to fix my difficulty.
> IDLE now works fine without hanging, I can enter code, save, check syntax,
> and run from the 'new window'.
> And 3.1 still works as before.
>
> regards,
> Bill
>
> --
> http://mail.python.org/mailman/listinfo/python-list
>
>


-- 
Jason M. Swails
Quantum Theory Project,
University of Florida
Ph.D. Graduate Student
352-392-4032
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