Python: programmatically running “pip list”

Question

I\'m writing a bit of code that will report and reconcile differences between two pip-managed python installations.

How can I programmatically get the information pr

Answer 1

Update for Python 3.6 and Pip 19.0.1

> from pip._internal.utils.misc import get_installed_distributions
> p = get_installed_distributions()
> pprint.pprint(p)

[wheel 0.32.3 (/usr/local/lib/python3.7/site-packages),
 wcwidth 0.1.7 (/usr/local/lib/python3.7/site-packages),
 virtualenv 16.0.0 (/usr/local/lib/python3.7/site-packages),
 virtualenv-clone 0.3.0 (/usr/local/lib/python3.7/site-packages),
 urllib3 1.24.1 (/usr/local/lib/python3.7/site-packages),
 typing 3.6.6 (/usr/local/lib/python3.7/site-packages),
 terminaltables 3.1.0 (/usr/local/lib/python3.7/site-packages),
 ...

Original Answer

Pip is just python module, so just import it and call list:

import pip

pip.main(['list'])

# you can get details on package using show:

pip.main(['show', 'wheel'])

Ok so there is better way:

pip.utils.get_installed_distributions()

returns you list of packages installed.

packages = pip.utils.get_installed_distributions()

p = packages[0]

p.project_name 
p.version
p.egg_name
p.location

You can see what pip list is doing from the source code here

Also get_installed_distributions accept whole bunch of parameters to return only local packages (from current virtualenv) etc. Please see help here.

There is also underlying low level command from _vendor module:

[p for p in pip._vendor.pkg_resources.working_set]

However get_installed_distributions provide simplier api.