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

For completeness, here's vittore's pip.main() idea fleshed out with the capture of stdout. Of course using get_installed_distributions() is the preferred solution.

import contextlib
@contextlib.contextmanager
def capture():
    import sys
    from cStringIO import StringIO
    oldout,olderr = sys.stdout, sys.stderr
    try:
        out=[StringIO(), StringIO()]
        sys.stdout,sys.stderr = out
        yield out
    finally:
        sys.stdout,sys.stderr = oldout, olderr
        out[0] = out[0].getvalue()
        out[1] = out[1].getvalue()

with capture() as out:
    import pip
    pip.main(['list'])

print out
    ['awscli (1.7.45)\nboto (2.38.0) ...