Multiple versions of python

[CCW]

On 21 July, 15:19, Dave Angel <da... at dejaviewphoto.com> wrote:
> ChrisW wrote:
> > Hi,
>
> > I have installed 2 versions of python on my Windows XP computer - I
> > originally had 3.0.1, but then found that the MySQL module only
> > supported 2.*, so I've now installed that.  I have found that if I
> > change the Windows Environment Variable path, then I can change the
> > version of python called when I type 'python' into a command line.
> > However, I'd like to be able to choose which version I use.  I know
> > that if I change C:\Python26\python.exe to
> > C:\Python26\python2.exe and C:\Python30\python.exe to C:
> > \Python26\python3.exe, then typing 'python2' or 'python3' will invoke
> > the correct interpreter.  However, is it safe just to rename the
> > executable files? Is there a more elegant way to achieve the same
> > task?
>
> > Thanks,
> > Chris
>
> The elegant way is to have a batch directory on your PATH ( I use  
> m:\t\bat )  and put your *.bat files there.   I do NOT put any python
> installations on the PATH.
>
> For example, I have a batch file called:     m:\t\bat\python26.bat
>
> c:\progfiles\python26\python.exe %*
>
> The %* syntax means pass all arguments through to the program.
>
> Once it all works, you can add an "@" in front of the c:   in order to
> suppress echoing the command.  At that point, it'll look and work the
> same way as what you did, but without modifying anything in the install
> directory.    (You may want  python26.bat, pythonw26.bat, python31.bat
> and pythonw31.bat)
>
> The other thing you may want to do in a batch file is to change the file
> associations so that you can run the .py file directly, without typing
> "python" or "pythonw" in front of it.
>
> The relevant Windows commands are:     assoc and ftype      And on a
> related note, you may want to edit the PATHEXT environment variable, to
> add .PY and .PYW

Thanks for this - this way made a bit more sense to me.  I've now got
C:\commands with the 4 .bat files in, and C:\commands in my path.  It
all seems to work :) I think I've missed the point of the @ though -
it doesn't seem to make any difference..

I'm also a bit confused with the associations - since I've got python
2.6 and 3.1, surely the command I type (python26 or python31) is the
only way to force a script to be run using a specific interpreter at
runtime without having to change the .bat file every time I want to
run a script using 3.1 instead of 2.6?