PyNoon Plus Lesson 4

Warm-Up Exercise

  • Think of questions or topics you’d like to bring up during our wrap-up discussion
  • Continue work on your Personal Python Project

Thanks

  • To the host for the great venue!
  • To our sponsors

Administrivia

  • Fire escapes
  • Toilets
  • Cleaning up after ourselves
  • Wi-Fi

PyNoon Finale: What Next?

  • 10,000 foot view of topics not covered so far
  • Recommendations for continuing learning
  • Wrap-up discussion - start thinking of questions

Object Oriented Programming (OOP)

  • Define data types (classes) that are used to create objects that store their own variables (attributes) and functions (methods)
  • Dataclasses are particularly great for storing a bunch of related variables:
from dataclasses import dataclass

@dataclass
class InventoryItem:
    """Class for keeping track of an item in inventory."""
    name: str
    unit_price: float
    quantity_on_hand: int = 0

    def total_cost(self) -> float:
        return self.unit_price * self.quantity_on_hand

my_item = InventoryItem(name='Notebook', unit_price=9.99, quantity_on_hand=5)
print(f'We have {my_item.total_cost()} worth of {my_item.name}')

Python Scripting

The command line

  • Every operating system has a command-line/command-prompt/terminal
  • It lets you run programs with text commands
    • Similar to the Python shell

Running other programs

  • Run commands from Python with:

Command line interfaces (CLIs)

argparse lets you specify arguments for a command-line interface:

Also see:

Internet-of-Things

  • Python libraries for connecting to IoT devices
    • E.g. xled for Twinkly lights

  • opencv and Pillow for processing video streams and images (e.g. home security)

Internet-of-Things

  • Raspberry Pi is a cheap and popular computer for IoT use cases
  • MicroPython for microcontrollers
  • Related: Send messages or build a bot for chat apps like Slack:
from slack_sdk import WebClient

client = WebClient(token='YOUR_SLACKBOT_TOKEN')

client.chat_postMessage(channel='#random', text='Hello world!')

Python Web Development

Flask - the simplest option

from flask import Flask

app = Flask(__name__)

@app.route("/")
def hello_world():
    return "<p>Hello, World!</p>"

Database-backed web applications

  • FastAPI - modern option for APIs
  • Django - saves you from re-inventing wheels
    • Wagtail - Content Management System for Django

Project Best Practices

Project structure

Documentation

  • Give variables, functions, and files informative names!
  • Write docstrings for your modules, functions, and variables
    • Follow a style guide for documenting arguments and return values
  • Use type hints to document and check the data types of function arguments and return values
  • MkDocs can generate documentation from Markdown files, docstrings, and type hints

Tooling

  • Manage pip dependencies with uv
  • Automated testing
  • Linting to check code style, e.g. ruff
  • Version control to track file changes, e.g. git
  • Set up lots of common tools with usethis

Miscellaneous

The Python Community

Continuing Your Learning

Wrap-Up Discussion

  • Would you be interested in a follow-up course?
  • Would you want to repeat this course?
  • Would you be interested in an on-going meetup?