Python Modules and Programs

Breaking down programming problems into their smallest pieces is one of the most critical skills in programming. You’ll need to practice this for the weekend assignment.

🗓️ Today’s topics

• Modules and import
• Program shape & design

🤓 How to approach a large project

tl;dr: Plan, be methodical, and talk to colleagues.

Sketch it out before you write code

Developers need to sketch out their ideas. (This is the true purpose of whiteboards for engineering teams, not grilling job candidates on obscure algorithms…) A pencil and paper is a great tool for programming. If that isn’t your style, use a stylus and tablet, a Google Doc, or whatever you like to jot things down. Don’t start in the code editor, in other words.

• What is the program/product’s purpose or goal? Restate it in your own words to be sure you get it.
• What is its core purpose? See if you can clear away anything not strictly necessary and get down to the simplest version of what it does.
• Bullet list out the main things it needs to do to achieve its purpose.
• Then go back and look at each bullet, and break it down further. What steps might need to happen first?
  • Each step could be something you know how to do OR something you don’t know how to do. Examples:
    • Get the contents of a file
    • Figure out some way to choose a random word
    • Keep track of what letters have been guessed
• Go back and re-read your list.
  • Are you missing any steps? Is there anything out of order?
  • Could any step be made clearer or more precise with more detail?
  • Is each step really just one step? Do you need to break them down into more than one, or do some steps need to be combined?
• Revise this list until it looks solid to you.
• Talk to other people working on this assignment and compare your lists.
• You will probably have to revisit your plan and revise it as you discover new problems to solve while you work. This is expected and ok. It is all in a day’s work for a software developer.

Once you have a plan you think is somewhat doable, then you can start writing code. Use pseudo-code to help guide you. Work through your steps in the order that makes sense, keeping in mind that you can hard-code values as placeholders where you need to.

🗝 You have to run your program repeatedly to get feedback about what is happening.

🗝 Don’t forget to use your print statements to give you necessary information as your program runs.

🗝 Change one thing at a time and work methodically.

🗝 Take breaks. It’s hard to think when you are tired, frustrated, or stressed.

🗝 Talk to other developers when you are stuck. Talking through the problem will often clarify what you need to do. See Rubber Duck Debugging.

🐍 Code Break

Try working with a module

🎯 Project

This is due on Thursday.

Mystery Word

🔖 Resources

• The Hitchhiker’s Guide to Python
• RealPython: Modules and Packages: We’ll get more into packages next week, so just read through the section on modules for now.
• RealPython: How to Run Your Python Scripts: Much of the beginning of this article is review of things we’ve talked through in class, but it is a good synthesis of what we’ve covered.
• Python Docs: Tutorial on Modules
• Python Docs: Module Index
• Python Docs: __main__

🦉 Code

• Python notebooks 12 - Modules