#85: Visually debugging your Jupyter notebook

Sponsored by DigitalOcean: pythonbytes.fm/digitalocean

Brian #1: the state of type hints in Python

• “Therefore, type hints should be used whenever unit test are worth writing.”
• Type hints, especially for function arguments and return values, help make your code easier to read, and therefore, easier to maintain.
• This includes refactoring, allowing IDEs to help with code completion, and allow linters to find problems.
• For CPython
  • No runtime type inference happens.
  • No performance tuning allowed.
  • Of course, third party packages are not forbidden to do so.
• Non-comment type annotations are available for functions in 3.0+
• Variable annotations for 3.6+
• In 3.7, you can postpone evaluation of annotations with: from __future__ import annotations
• Interface stub files .pyi files, are allowed now, but this is extra work and code to maintain.
  • typeshed has types for standard library plus many popular libraries.
• How do deal with multiple types, duck typing, and more discussed.
• A discussion of type generation and checking tools available now, including mypy
• See also: Stanford Seminar - Optional Static Typing for Python - Talk by Guido van Rossum
  • Interesting discussion that starts with a bit of history of where mypy came from.

Michael #2: Django MongoDB connector

• Via Robin on Twitter
• Use MongoDB as the backend for your Django project, without changing the Django ORM.
• Use Django Admin to access MongoDB
• Use Django with MongoDB data fields: Use MongoDB embedded documents and embedded arrays in Django Models.
• Connect 3rd party apps with MongoDB: Apps like Django Rest Framework and Viewflow app that use Django Models integrate easily with MongoDB.
• Requirements:
  • Python 3.6 or higher.
  • MongoDB 3.4 or higher.
• Example

  inner_qs = Blog.objects.filter(namemd5-f73ff5c48f5ff9c498911466c19a1050name__in=inner_qs)
  

Brian #3*: Python Idioms: Multiline Strings*

• or “How I use dedent”
• Example:

    def create_snippet():
        code_snippet = textwrap.dedent("""\
            int main(int argc, char* argv[]) {
                return 0;
            }
        """)
        do_something(code_snippet)

Michael #4: Flaskerizer

• A program that automatically creates Flask apps from Bootstrap templates
• Bootstrap templates from websites like https://Bootstrapmade.com/ and https://startBootstrap.com are a fast way to get very dynamic website up and running
• Bootstap templates typically don't work "out of the box" with the python web framework Flask and require some tedious directory building and broken link fixing before being functional with Flask.
• The Flaskerizer automates the necessary directory building and link creation needed to make Bootstrap templates work "out of the box" with Flask.
• Queue black turtleneck!

Brian #*5: Learn Python the Methodical Way

• From the article:
  • Make your way through a tutorial/chapter that teaches you some discrete, four-to-six-step skill.
  • Write down those steps as succinctly and generically as possible.
  • Put the tutorial/chapter and its solutions away.
  • Build your project from scratch, peeking only when you’re stuck.
  • Erase what you built.
  • Do the project again.
  • Drink some water.
  • Erase what you built and do it again.
  • A day or two later, delete your work and do it again – this time without peeking even once.
  • Erase your work and do it again.
• The notion of treating code like you treat creative writing with rough drafts and sometimes complete do-overs is super liberating.
• You’ll be surprised how fast you can do something the second time, the third time, the fourth time. And it’s very gratifying.

Michael #6: PixieDebugger

• The Visual Python Debugger for Jupyter Notebooks You’ve Always Wanted
• Jupyter already supports pdb for simple debugging, where you can manually and sequentially enter commands to do things like inspect variables, set breakpoints, etc.
• Check out the video to get a good idea of its usage: https://www.youtube.com/watch?v=Z-tPeEkVqjk