In a Python IDE, just copy and paste in the following code and run it (the version will come up in the output area):

import sys
print(sys.version)

I use a single _version.py file as the "once cannonical place" to store version information:

1. It provides a __version__ attribute.

2. It provides the standard metadata version. Therefore it will be detected by pkg_resources or other tools that parse the package metadata (EGG-INFO and/or PKG-INFO, PEP 0345).

3. It doesn't import your package (or anything else) when building your package, which can cause problems in some situations. (See the comments below about what problems this can cause.)

4. There is only one place that the version number is written down, so there is only one place to change it when the version number changes, and there is less chance of inconsistent versions.

Here is how it works: the "one canonical place" to store the version number is a .py file, named "_version.py" which is in your Python package, for example in myniftyapp/_version.py. This file is a Python module, but your setup.py doesn't import it! (That would defeat feature 3.) Instead your setup.py knows that the contents of this file is very simple, something like:

Copy__version__ = "3.6.5"

And so your setup.py opens the file and parses it, with code like:

Copyimport re
VERSIONFILE="myniftyapp/_version.py"
verstrline = open(VERSIONFILE, "rt").read()
VSRE = r"^__version__ = '\"['\"]"
mo = re.search(VSRE, verstrline, re.M)
if mo:
    verstr = mo.group(1)
else:
    raise RuntimeError("Unable to find version string in %s." % (VERSIONFILE,))

Then your setup.py passes that string as the value of the "version" argument to setup(), thus satisfying feature 2.

To satisfy feature 1, you can have your package (at run-time, not at setup time!) import the _version file from myniftyapp/__init__.py like this:

Copyfrom _version import __version__

Here is an example of this technique that I've been using for years.

The code in that example is a bit more complicated, but the simplified example that I wrote into this comment should be a complete implementation.

Here is example code of importing the version.

If you see anything wrong with this approach, please let me know.

The version typical in the ‘init.py’ file, not version. It’s for storing the version of the software, so you can access it at runtime.