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Is there a way in Python to list all installed packages and their versions?

I know I can go inside python/Lib/site-packages and see what files and directories exist, but I find this very awkward. What I'm looking for something that is similar to npm list i.e. npm-ls.

If you have pip install and you want to see what packages have been installed with your installer tools you can simply call this:

pip freeze

It will also include version numbers for the installed packages.

Update

pip has been updated to also produce the same output as pip freeze by calling:

pip list

Note

The output from pip list is formatted differently, so if you have some shell script that parses the output (maybe to grab the version number) of freeze and want to change your script to call list, you'll need to change your parsing code.

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help('modules') should do it for you.

in IPython :

In [1]: import                      #import press-TAB
Display all 631 possibilities? (y or n)
ANSI                   audiodev               markupbase
AptUrl                 audioop                markupsafe
ArgImagePlugin         avahi                  marshal
BaseHTTPServer         axi                    math
Bastion                base64                 md5
BdfFontFile            bdb                    mhlib
BmpImagePlugin         binascii               mimetools
BufrStubImagePlugin    binhex                 mimetypes
CDDB                   bisect                 mimify
CDROM                  bonobo                 mmap
CGIHTTPServer          brlapi                 mmkeys
Canvas                 bsddb                  modulefinder
CommandNotFound        butterfly              multifile
ConfigParser           bz2                    multiprocessing
ContainerIO            cPickle                musicbrainz2
Cookie                 cProfile               mutagen
Crypto                 cStringIO              mutex
CurImagePlugin         cairo                  mx
DLFCN                  calendar               netrc
DcxImagePlugin         cdrom                  new
Dialog                 cgi                    nis
DiscID                 cgitb                  nntplib
DistUpgrade            checkbox               ntpath
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    • I think the problem is theres no standardised way of including the version ... sometimes its Package.version() or package.__version__ or package.ver or any number of other possibilities
    • @EdRandall, no - it's "one obvious way to do it". There's always an unobvious way. Also, the exact wording is: There should be one-- and preferably only one --obvious way to do it. Although that way may not be obvious at first unless you're Dutch.

If you want to get information about your installed python distributions and don't want to use your cmd console or terminal for it, but rather through python code, you can use the following code (tested with python 3.4):

import pip #needed to use the pip functions
for i in pip.get_installed_distributions(local_only=True):
    print(i)

The pip.get_installed_distributions(local_only=True) function-call returns an iterable and because of the for-loop and the print function the elements contained in the iterable are printed out separated by new line characters (\n). The result will (depending on your installed distributions) look something like this:

cycler 0.9.0
decorator 4.0.4
ipykernel 4.1.0
ipython 4.0.0
ipython-genutils 0.1.0
ipywidgets 4.0.3
Jinja2 2.8
jsonschema 2.5.1
jupyter 1.0.0
jupyter-client 4.1.1
#... and so on...
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    • To expand on @exhuma's comment, with pip 10 you should use: import pkg_resources [print(d.project_name) for d in pkg_resources.working_set]
    • What's the state of pkg_resources? AFAICR this is part of setuptools. Not pip. Can we safely assume that setuptools will always be available ehen only depending on pip?

You can try : Yolk

For install yolk, try:

easy_install yolk

Yolk is a Python tool for obtaining information about installed Python packages and querying packages avilable on PyPI (Python Package Index).

You can see which packages are active, non-active or in development mode and show you which have newer versions available by querying PyPI.

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      • 2
    • I usually use pip for this task at this point, but I have a very old project that I'm not ready to add distribute into, and I remembered there was a tool like this out there. Couldn't remember what it was called though... This was it!

To run this in later versions of pip (tested on pip==10.0.1) use the following:

from pip._internal.operations.freeze import freeze
for requirement in freeze(local_only=True):
    print(requirement)
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    • What is the status of internal?. I see pydoc pip._internal but I cant reach it under help(pip._internal), pip.__builtins_ etc. pip reference guide is also blank.
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    • Unfortunately I don't know. I don't like it being called _internal either. It seems the functionality is not officially exposed. So you should handle this with care!

yes! you should be using pip as your python package manager ( http://pypi.python.org/pypi/pip )

with pip installed packages, you can do a

pip freeze

and it will list all installed packages. You should probably also be using virtualenv and virtualenvwrapper. When you start a new project, you can do

mkvirtualenv my_new_project

and then (inside that virtualenv), do

pip install all_your_stuff

This way, you can workon my_new_project and then pip freeze to see which packages are installed for that virtualenv/project.

for example:

?  ~  mkvirtualenv yo_dude
New python executable in yo_dude/bin/python
Installing setuptools............done.
Installing pip...............done.
virtualenvwrapper.user_scripts creating /Users/aaylward/dev/virtualenvs/yo_dude/bin/predeactivate
virtualenvwrapper.user_scripts creating /Users/aaylward/dev/virtualenvs/yo_dude/bin/postdeactivate
virtualenvwrapper.user_scripts creating /Users/aaylward/dev/virtualenvs/yo_dude/bin/preactivate
virtualenvwrapper.user_scripts creating /Users/aaylward/dev/virtualenvs/yo_dude/bin/postactivate
virtualenvwrapper.user_scripts creating /Users/aaylward/dev/virtualenvs/yo_dude/bin/get_env_details

(yo_dude)?  ~  pip install django
Downloading/unpacking django
  Downloading Django-1.4.1.tar.gz (7.7Mb): 7.7Mb downloaded
  Running setup.py egg_info for package django

Installing collected packages: django
  Running setup.py install for django
    changing mode of build/scripts-2.7/django-admin.py from 644 to 755

    changing mode of /Users/aaylward/dev/virtualenvs/yo_dude/bin/django-admin.py to 755
Successfully installed django
Cleaning up...

(yo_dude)?  ~  pip freeze
Django==1.4.1
wsgiref==0.1.2

(yo_dude)?  ~  

or if you have a python package with a requirements.pip file,

mkvirtualenv my_awesome_project
pip install -r requirements.pip
pip freeze

will do the trick

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    • Oh yeah I've been using virtualenv actually for some time. I just don't know how I didn't figure out I can use pip along with it in this way!
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    • Using global site packages is very useful. If it wasn't, the option wouldn't exist at all in virtualenv. I am not aware of any reason for not using them, and nobody prevents you from restricting to isolated virtualenv if you prefer.
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    • One great reason to not use them is that when you distribute or deploy your app or program, other people/servers won't have your global site packages. If you're the only person using the app, then do whatever you want.

Here's a way to do it using PYTHONPATH instead of the absolute path of your python libs dir:

for d in `echo "${PYTHONPATH}" | tr ':' '\n'`; do ls "${d}"; done

[ 10:43 Jonathan@MacBookPro-2 ~/xCode/Projects/Python for iOS/trunk/Python for iOS/Python for iOS ]$ for d in `echo "$PYTHONPATH" | tr ':' '\n'`; do ls "${d}"; done
libpython2.7.dylib pkgconfig          python2.7
BaseHTTPServer.py      _pyio.pyc              cgitb.pyo              doctest.pyo            htmlentitydefs.pyc     mimetools.pyc          plat-mac               runpy.py               stringold.pyc          traceback.pyo
BaseHTTPServer.pyc     _pyio.pyo              chunk.py               dumbdbm.py             htmlentitydefs.pyo     mimetools.pyo          platform.py            runpy.pyc              stringold.pyo          tty.py
BaseHTTPServer.pyo     _strptime.py           chunk.pyc              dumbdbm.pyc            htmllib.py             mimetypes.py           platform.pyc           runpy.pyo              stringprep.py          tty.pyc
Bastion.py             _strptime.pyc          chunk.pyo              dumbdbm.pyo            htmllib.pyc            mimetypes.pyc          platform.pyo           sched.py               stringprep.pyc         tty.pyo
Bastion.pyc            _strptime.pyo          cmd.py
....
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If this is needed to run from within python you can just invoke subprocess

from subprocess import PIPE, Popen

pip_process = Popen(["pip freeze"], stdout=PIPE,
                   stderr=PIPE, shell=True)
stdout, stderr = pip_process.communicate()
print(stdout.decode("utf-8"))
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