Friday, July 27, 2018

Learning Python 3

Updated September 10th, 2022

Here are some of the resources I used to start learning python. With my newly learned  Python skills and some Google-Fu I have been able to automate several network device tasks. You can find most of my python scripts at Hubbard on Networking GitHub Repo.

You do NOT need to know anything about python to use the scripts. This is just like you don't have to know how to program to run "show interface g1/0/1". You simply download the script and execute it.

I found this tweet that has a curated list of python resources:


Why You Should Learn Python

A lot of the tasks that network engineers perform are repetitive, mind-numbing, and error-prone. With a little python skill, you can automate these tasks and spend the time you save on more productive tasks, like learning more python.

As networking moves away from the CLI and into software-defined networking (SDN) you will need to have some dev skills. Cisco has a three-part video on how the network engineer's job is changing. You will need to register with Cisco Devnet to watch it but you should have a Devnet account if you going down this path:
Lesson 1: The Network Engineer of Old

If you have never used Python at all, this blog is the place to get started!

First, to install python, head over to the Python download page - Download Python
Follow the instructions to install python on your OS of choice.

Tools

There isn't much needed to use Python other than python itself but like most things, life is easier with some tools.

Integrated Development Environment (IDE)

IDEs are tools that allow you to write and debug code. Once you start writing scripts that are more than a few lines long you will want to use an IDE.

Thonny - Python IDE for beginners. A free Integrated Development Environment. This tool is great for learning. It lets you step through a script and see exactly what is happening.

MU - a simple Python editor for beginner programmers. This one is really nice. It's cross-platform and has support for Linux, Mac, Windows, and Raspian. What separates it from the other tools listed here is the support for small devices like Adafruit and Micro:bit. Here is a screenshot of MU starting up:



Microsoft Visual Studio Code - A free open source IDE from Microsoft. VSCode has turned into an amazing development environment and can be used for any size project. It has an integrated debugger that looks just like the Powershell ISE tool. It supports almost every programming language, not just python. The open-source version of PowerShell is fully supported which is great. I can use one tool and create Python and PowerShell scripts. 

There is a Visual Studio Marketplace with thousands of plugins, similar to the Chrome store or Firefox store. Extensions for the Visual Studio family of products

I have more detail on my macOS blog. Once you have VScode installed it works the same on Windows, Mac, and Linux so the blog is useful regardless of what OS you use. My VSCode install blog

Code Editor

You can definitely use VSCode as your editor. It has about every feature that you could want. But I have been using Sublime text since before VSCode came out and old habits die hard! If you are on Ubuntu 22.04 you can install Gnome Text Editor (I know, really, really stupid name) and it works great for quick editing.

Sublime text - Sublime is a text editor that is optimized for programming. It has a huge community around it and thousands of plugins. It's $75.00 but the license lets you run it on as many machines as you own. I bought it and installed it on my Linux, Windows, and Mac laptops. It has a tabbed interface like notepad++ which I like. You can also split the screen and open two files side by side. This is useful because you can have your script on one side and the data file on the other. 

Realpython.com sells a great tutorial that walks you through installing Sublime text optimized for Python. It includes video and text for Mac, Linux, and Windows. This tutorial is well worth the cost and has improved my productivity in Sublime.

In the next section, I discuss revision control with Git. Sublime text has several plugins that integrate Git into your workflow.  One I really like is Git Gutter. It puts a + sign next to lines that have changed, then you can revert easily if the change didn’t work.
Your Shortcut to a Professional Python Development Setup

Revision Control

Git - A revision control system. It's useful once you start writing scripts large enough to have bugs or future enhancements. Even if you don't program in python it's worth installing git because of github.com and gitlab.com.

Both of these sites have thousands of python tools. If you have git installed on your computer all you have to do to use them is "git clone <repository>". For example, to install the ARP sorting tool I wrote, you simply go to ARP-Sort and click the "Code" button. It will display the URL for the project. Click the copy button, type “git clone” and paste the URL you copied into the terminal, then press enter:

git clone https://github.com/rikosintie/ARP-Sort.git

This downloads the project and unzips it into the folder ARP-Sort.




Someone has created an online game for learning Git - An open source game about learning Git!
Cisco DevNet GitHub Repo - Great resources on setting up your laptop with Python, Git, Postman, etc.
Git and GitHub for Beginners - Crash Course - A really good video on git.
 


Videos from Udemy.com 

Udemy has inexpensive video training for Python, Linux, and a lot of other applications. These are on sale all the time for $9.99

  • Python Network Programming - Part 1: Build 7 Python Apps
  • Complete Python Bootcamp: Go from zero to hero in Python 3
  • 100 Days of Code - The Complete Python Pro Bootcamp for 2021

Videos on Youtube

I find that I learn better when using books and websites but sometimes it's nice to watch a video.

Real python did a blog on the best Youtube channels for python
The Ultimate List of Python YouTube Channels

Subscribe to HackerSploit on Youtube and there is a complete series on Python. He uses 2.7 but it is still a good tutorial. They are really basic but I find Alexis entertaining.
Python For Ethical Hacking - #1 - Introduction & Python Modules

Telusko Python for Beginners
Python Tutorial - Python for Beginners [Full Course] - Mosh 
Learn Python - Full Course for Beginners [Tutorial] Free Code Camp
Writing Pythonic Code - A Tweet thread by @Bascodes. He is worth following.

Corey Shafer Videos

I recommend that you subscribe to this channel. Here are four of his videos that I found very useful

Requests Tutorial - The requests library is used to pull data down from webservers
JSON Tutorial - Java Script Object Notation is a common data format used by APIs
Sorting Tutorial - Sorting routines for lists and dictionaries
List Comprehensions - Working with list comprehensions

e-books from Amazon  

I love the Kindle app on my laptop, phone and iPad. If I get stuck in a long line I just open it up and do some studying! These were all under $5. You can go to Amazon, set filter to Kindle store and enter "python programming free book" and find a lot of free books.

  • Learn Python in One Day and Learn It Well Python for Beginners with Hands-on Project The only book you need to start coding in Python immediately By Jamie Chan
  • Python Tips and Tricks: Learn the Best Tips and Tricks to Get The Most out of Python NOW! Jones, Daniel
  • The Fundamentals Of Python Programming: A Complete Beginners Guide To Python Mastery.
  • Python Programming Tips and Tricks: The Ultimate Cheat Sheet for Python Programming. 20+ Tips and Tricks to Make Your Life Easier and More Efficient
  • Automate the Boring Stuff with Python: Practical Programming for Total Beginners


Websites

There are so many python websites it would be impossible to list them all, here are a few I have found very useful:

Getting Started

General Tips

Jinja Templates

Network Engineering

Debugging

Web Development


Style guides

Python is a structured language that uses white space as part of the structure. But you can still create ugly code. The official Python style guide is part of the Python Enhancement Proposals (PEPs) which are documents that provide guidance and spell out best practices for how Python code should be organized, packaged, released, deprecated, and so on. PEP8 is a popular standard for styling Python code and is extensively used in the developer community. 

Python Virtual Environments

As you start learning and creating more python tools you will want to start using virtual environments. These two blogs will teach you what you need to know. There are a lot more blogs available on the Internet.

Podcasts

You probably won't learn much coding from a podcast but these are very interesting to listen to. I find a lot of good links in the show notes. For example, I learned about Thonny, MU, and Visual Studio Code from podcasts.
Talk Python To Me - A good podcast that covers a lot of topics. There will be one called "Teaching Python to network engineers" in August, 2018!
Podcast.__init__ - A podcast about Python and the people who make it great. Hosted by Tobias Macey.
Python Bytes - Python Bytes podcast delivers headlines directly to your earbuds. If you want to stay up on the Python developer news but don’t have time to scour Reddit, Twitter, and other news sources, just subscribe and you’ll get the best picks delivered weekly.

Keywords In Python

There are 33 keywords that should never be used as a variable, function name, class, object, or as any other identifiers in your programs.

 false
 True
 finally
 class
 for
 continue
 none
 return
 lambda
 try
 is
 def
 from
 nonlocal
 while
 and
 not
 global
 del
 with
 as
 elif
 if
 or
yield
 break
 import
 except
 pass
 assert
 else
 raise
 in

Libraries

Pint - Pint is a Python package to define, operate and manipulate physical quantities

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