Python 2 or Python 3? Asked and Answered.

I’ve spent the last 6 months converting my Python 2.7 scripts over to Python 3. In the nascent days of SDN and Automation that was always one of the first questions asked… To code in Python 2 or Python 3?

That question has been answered.

If you look at the Python Developers Guide you can see the expiration date quite clearly and looking at PEP 373 gives you a real sense of the history.

There will be some niche projects that keep 2.7 going I suspect, however as this question relates to network automation the answer is clear.

It’s time to embrace Python 3.

If you are just getting started, download Python 3 and move along. No need to read this!

For those who started with Python 2, the key impediments are gone. For me Ansible was the last hold out. Starting with Ansible 2.2 (11-01-2016) we saw the effort to move the code base to Python 3. Officially, as of Ansible 2.5.0 (Released 2018-03-22), Python 3 (specifically 3.5 or later) is supported.

All the modules commonly used by network engineers are mature on Python 3.

  • Netmiko
  • Napalm
  • Ciscoconfparse
  • TextFSM

If the imminent “end of life” of Python 2 is not enough there are some real benefits to moving to Python 3. There are features in Python 3 that will help you if you are beginner:

and features that will help you if you are more advanced:

just to highlight two of my favorites.

Python 3 also comes with a built-in ipaddress module. I’m a big fan of netaddr which is absolutely available in Python 3 but if you want to share your code and keep dependencies down this is a big plus.

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