Parallel Python x.y.A and x.y.B installations on a single Windows machine

Jurko Gospodnetić jurko.gospodnetic at
Mon Nov 25 13:32:30 CET 2013

   Hi all.

   I was wondering what is the best way to install multiple Python 
installations on a single Windows machine.

   Regular Windows installer works great as long as all your 
installations have a separate major.minor version identifier. However, 
if you want to have let's say 2.4.3 & 2.4.4 installed at the same time 
it does not seem to work.

   I have not been able to find any prepackaged Python installation or 
really any solution to this. Most of the advice seems to boil down to 
'do not use such versions together, use only the latest'.

   We would like to run automated tests on one of our projects (packaged 
as a Python library) with different Python versions, and since our code 
contains workarounds for several problems with specific Python patch 
versions, we'd really like to be able to run the tests with those 
specific versions and with as little fuss as possible.

   Looking at what the Python installer does, the only problematic part 
for working around this manually seems to be the registry entries under 
'Software\Python\PythonCore\M.m' where 'M.n' is the major.minor version 
identifier. If Python interpreter expects to always find its entries 
there, then I guess there is no way to do what we need without building 
customized Python executables. Is there a way to force a specific Python 
interpreter to not read in this information, read it from an .ini file 
or something similar?

   Many thanks.

   Best regards,
     Jurko Gospodnetić

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