[Neuroimaging] Technical details managing Python versions and packages.

[Yaroslav Halchenko]

On Mon, 03 Aug 2015, Matthew Brett wrote:

> >> You can also easily junk a set of installs with:

> >> rmvirtualenv my-env

> >> How do you do that?

> > not sure on specifics of this question -- "rm -rf my-env"? ;)  My
> > virtualenvs aren't usually long-lived.

> Sorry - I only meant that - if I do say apt-get install python-vtk -
> then I will get that package and all the relevant dependencies, as
> decided by the packager.  Then I will get those packages in all my
> virtualenvs with ``--system-site-packages``, past and present, which
> might change their behavior.  

that is right!  and if my package depends on that behavior, and starts
to fail -- I better know that! ;)

> So I can't easily do evanescent installs
> of these packages, as I can with the wheels / virtualenvs approach.

noone forbids you to use virtualenv without --system-site-packages if
pypi-as-of-today-pristine  state is what you want/need.  In my case I
rarely need/want a sanitarization at this level.

-- 
Yaroslav O. Halchenko, Ph.D.
http://neuro.debian.net http://www.pymvpa.org http://www.fail2ban.org
Research Scientist,            Psychological and Brain Sciences Dept.
Dartmouth College, 419 Moore Hall, Hinman Box 6207, Hanover, NH 03755
Phone: +1 (603) 646-9834                       Fax: +1 (603) 646-1419
WWW:   http://www.linkedin.com/in/yarik