Coexistence of Python 2.x and 3.x on same OS

[Edward Diener]

On 10/1/2012 1:32 PM, Dennis Lee Bieber wrote:
> On Sun, 30 Sep 2012 23:06:04 -0400, Edward Diener
> <eldiener at tropicsoft.invalid> declaimed the following in
> gmane.comp.python.general:
>
>
>> My thought is a program distributed by Python which finds the versions
>> of Python on an OS, lets the end-user choose which version should be
>> invoked when Python is invoked, and does whatever is necessary to make
>> that version the default version.
>>
> 	Which wouldn't be usable on any system that has to boot/process
> unattended, and run's Python scripts for configuration set-up.

I can understand that but my use of Python on Windows is not that case. 
I simply want to be able to choose which version of Python runs when it 
is invoked, when I have multiple versions installed. Surely that is a 
very common case for end-users running 'python' or invoking some script 
which is associated with python.

>
> 	Making a version "default" pretty much means being able to rewrite
> the PATH environment variable... And I've seen too many messes made by
> some software already (including once having two generations of Python
> showing up in one PATH!)

The PATH environment is constantly changing whether in Linux or Windows. 
Claiming that this is too dangerous" is silly.