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Improve Your Python: Python Classes and Object Oriented Programming

Note: Each day this week I'm going to republish one of my most popular posts. My hope is that people who missed them the first time might find them useful now. This post, on "classes" and Object Oriented Programming remains my most popular post of all time. I've gotten hundreds of emails about this post alone. Many have found it an accessible introduction to classes and OOP, both in Python and in general.

The class is a fundamental building block in Python. It is the underpinning for not only many popular programs and libraries, but the Python standard library as well. Understanding what classes are, when to use them, and how they can be useful is essential, and the goal of this article. In the process, we'll explore what the term Object-Oriented Programming means and how it ties together with Python classes.

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How Python Linters Will Save Your Large Python Project

A Python project I'm working on at Enigma is starting to grow rather large. I spent a good deal of effort yesterday getting a five line change added to our Makefile (which is run as part of our CI and CD pipeline on every pull request and merge). After the PR was merged, I gloated to others how awesome my team's project was. Here are the five lines:

lint:
    pylint --rcfile=.pylintrc api -f parseable -r n && \
    mypy --silent-imports api && \
    pycodestyle api --max-line-length=120 && \
    pydocstyle api

For completeness sake, here is the test target that actually gets run as part of CI tests:

test: install lint
    python3 setup.py test --addopts="--cov=api"
    coverage xml -i -o coverage/cobertura-coverage.xml --omit=$(VIRTUAL_ENV)/*,.eggs/*

(So, for those not versed in "Makefile-ese", the test target won't run successfully if the lint target doesn't do so first).

Why was I happy enough to be a jerk to other engineers and brag about those five lines? It all comes down to complexity.

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How Python Makes Working With Data More Difficult in the Long Run

Before we begin, let's be clear on terminology. When I refer to "working with data" in the context of software development I could mean one of two things:

  1. Interactively working with data, with perhaps Jupyter (née IPython) or the live interpreter
  2. Writing, testing, reading, reviewing and maintaining programs that primarily manipulate data

In short: Python is awesome for interactive data analysis but terrible for writing long-lived programs dealing with complicated data structures.

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