[IPython-user] A bag of pythons on OS X leopard; Is a house cleaning in order.

Robin robince@gmail....
Wed Oct 8 12:24:00 CDT 2008

On Wed, Oct 8, 2008 at 5:55 PM, Barry Wark <barrywark@gmail.com> wrote:
> On Wed, Oct 8, 2008 at 1:01 AM, Robin <robince@gmail.com> wrote:.
> Not true. The system python, by default, will put its version of numpy
> first on the python path (to protect Apple-installed tools that depend
> on numpy). The system python comes with setuptools, however, for a
> reason. If you use setuptools to install a more recent version of
> numpy, setuptools will take care of putting the new version of numpy
> first on the python path while allowing Apple-installed tools to
> continue to use the version that shipped with Leopard.
> So the general rule is: use setuptools and things will "just work".

That sounds great - but I'm curious as to how it can work without
modifying stuff...

If I have a raw system python prompt and I do "import numpy" - what
determines which one I get? Sometimes I might want the new numpy (ie
when working on my own scripts) but sometimes I (or some downloaded
application assuming a standard system Python install) might want the
old numpy. If both of these are just doing "import numpy" how does
setuptools decide which one to serve up?

Another possible reason for using seperate python - if an operating
system upgrade changes the python version (ie 2.5 -> 2.6) then won't
that break all your installed modules built against the old version?

If using macports python, there is a good chance it'll carry on
working after an upgrade... (it did for me with Leopard)


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