[Distutils] Packages listed in Easy-Install.pth

[P.J. Eby]

At 11:19 PM 3/9/2009 -0400, David Lyon wrote:

>What I want to do is use these in a list of installed packages. And then
>later provide for deinstallation. I'm thinking of parsing this file to read
>all the package names..
>
>My question is is there any way to do the same thing with setuptools?

http://peak.telecommunity.com/DevCenter/PkgResources#workingset-objects

You can simply iterate over pkg_resources.working_set to obtain 
Distribution objects for all eggs on sys.path -- that will give you 
all *activated* packages (i.e., ones listed in .pth files or 
otherwise explicitly on sys.path).

If you want all *installed* packages (which may not be on sys.path, 
but are still physically present in a directory on sys.path), you 
want an Environment object instead:

http://peak.telecommunity.com/DevCenter/PkgResources#environment-objects

And to remove a package from the .pth file, you can use "easy_install 
-mxNd targetdir project==version" -- this will remove the named 
project from the easy-install.pth file in targetdir.  (The -m takes 
it out, the -x means don't reinstall scripts, the -N means don't 
install dependencies, and the -d targetdir specifies where the .pth file is.)