How to check version of python modules?

Question

I just installed the python modules: construct and statlib with setuptools like this:

# Install setuptools to be able to download the following
sudo apt-get install python-setuptools

# Install statlib for lightweight statistical tools
sudo easy_install statlib

# Install construct for packing/unpacking binary data
sudo easy_install construct

I want to be able to (programmatically) check their versions. Is there an equivalent to python --version I can run from the command line?

My python version is 2.7.3.

Answer 1

I suggest using pip in place of easy_install. With pip, you can list all installed packages and their versions with

pip freeze

In most linux systems, you can pipe this to grep(or findstr on Windows) to find the row for the particular package you're interested in:

Linux:
$ pip freeze | grep lxml
lxml==2.3

Windows:
c:> pip freeze | findstr lxml
lxml==2.3

For an individual module, you can try the __version__ attribute, however there are modules without it:

$ python -c "import requests; print(requests.__version__)"
2.14.2
$ python -c "import lxml; print(lxml.__version__)"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
AttributeError: 'module' object has no attribute '__version__'

Lastly, as the commands in your question are prefixed with sudo, it appears you're installing to the global python environment. Strongly advise to take look into python virtual environment managers, for example virtualenvwrapper