Looking for tips on running Python version 2.6 and 3.0 together on same *WINDOWS* machine

Jason Scheirer jason.scheirer at gmail.com
Wed Feb 25 07:49:19 CET 2009

On Feb 24, 9:20 pm, "Martin v. Löwis" <mar... at v.loewis.de> wrote:
> > It's easy - the registry isn't used except to associate files. The
> > associations are made with the most-recently-installed version.
> > I currently have 2.4, 2.5, 2.6 and 3.0 on my Windows machine.
> In addition, at install time, there is the choice of not creating
> associations (i.e. links what interpreter should be invoked if you
> double-click a .py file, and what version of IDLE should start
> when you select Edit from the context menu).
> So if you install 2.6 first, then 3.0, but deselect the installation
> of associations, 2.6 will continue to be associated with the
> .py, .pyw, and .pyc extensions.
> Regards,
> Martin

Technically not true. Python DOES use the registry, but it's per-
version and isolated from each other. Each installs some configuration
data in HKEY_LOCAL_MACHINE\\Software\Python\PythonCore\MAJOR.MINOR, so
you'll have stuff in HKLM\\Software\Python\PythonCore\2.6 and HKLM\
\Software\Python\PythonCore\3.0. And yes, this DOES mean you can't
have 2.6 and 2.6.1 cleanly installed on the machine at the same time.

As long as you keep your .py and .pyw files associated with the
preferred Python interpreter (2.6 I'm assuming) and EXPLICTLY call C:
\Python30\Python.exe when you want to run on 3.0, you're golden.

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