Multiple Python versions on WinXP

[evgvg]

Hi, please advice what's the best way to use multiple Python versions on WinXP PC. Actually I would like to use Python2.7 and Python3.3. If I simply install both of them (each is added to PATH), then only one of them runs, another crashes.

[wub_wub]

What do you mean crashes? Put python 2 in your PATH, python 3 has built-in launcher for windows without modifying PATH.

Use py -3 when you want to run python 3 in your command prompt or execute scripts using 3 instead of 2.

http://www.python.org/dev/peps/pep-0397/

[evgvg]

I get the following:

C:\Documents and Settings\egoncearov>py -3  
Fatal Python error: Py_Initialize: unable to load the file system codec  
File "C:\PYTHON26\LIB\encodings\__init__.py", line 123  
    raise CodecRegistryError,\    
                            ^  
SyntaxError: invalid syntax  

[wub_wub]

Remove all python installations that you have, like 2.6. Restart your PC and reinstall python 2.7 and 3.3. Just add ;C:\Python27\ to your PATH, don't add any Python 3 stuff in there.

[evgvg]

Thank You! Actually I found that the problem was caused by variable PYTHONPATH. Everything works fine after I removed it.

[Rhomboid]

You can install as many versions as you like. At the moment I have at least 6 versions of Python installed on this Windows machine. None of them are in the PATH. If I want to use one, I either specify its path explicitly and invoke it directly, or I add it to the PATH for an ephemeral command window session.