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Good Habits in Coding

Learning Objectives
  • Identify good and bad habits in coding
  • Use a style guide to write code
  • Use VSCode effectively by using shortcuts and features
  • Use type hints in Python function definitions
  • Explain the benefits of using type hints in Python

Pre-work​

Setup​

If nobody has done so already, copy and paste this command into slack

/prework Good Habits

Read​

Review our Internal Style Guide

https://coda.io/d/Trainees_dryBdidTdcn/Code-Style-Guide_suBej#_luf2v

And skim read the PEP8 Style Guide

https://pep8.org/

Think​

Task

Consider the following questions carefully:

  • Why are style guides important?
  • What are the repercussions of not following a style guide?

Don't share these yet; we'll discuss in the session.

Research​

Task

Research VSCode keyboard shortcuts.

Find three that you think will be useful to you.

Task

Research terminal keyboard shortcuts.

Find three that you think will be useful to you.

Workshop​

Live Code​

Ask the trainees for reasons that using a style guide is important.

  • It makes code easy to read
  • It lets us collaborate better
  • It makes it easier to debug
  • It makes it easier to maintain
  • It makes it easier to refactor
  • It makes it easier to test
  • It makes it easier to document
  • You write code once, but read it many times - optimise for reading.

Give the below code to the trainees (using Slack code blocks) and ask them to identify what is wrong with it.

import random

def check(str, guess):
    result = ['_' for _ in range(len(str))]
    for i, x in enumerate(guess):
        if x == str[i]:
            result[i] = x
        elif letter in str:
            result[i] = '?'
    return result

def gen_wor(wlist):
    return random.choice(wlist)

def func():
    i = gen_wor()
    go = 5
    while go > 0:
        input1 = input("Enter your guess: ")
        if len(i) != 5:
            print("Please enter a 5-letter word.")
            continue
        result = check(i, input1)
        print(' '.join(result))
        if input1 == i:
            print("Congratulations! You've guessed the word.")
            return
        go -= 1
    print(f"Sorry, you didn't guess the word. The word was {i}.")

list2 = ["apple", "place", "grape", "chair", "spear", "green", "plant", "house", "water", "money", "tiger", "panda"]
func(list2)

Highlight that the style makes it confusing and hard to read.

Explain that you can use pylint to check your code for errors and style issues.

Demonstrate this by running pylint on the code above.

Show how you can use the pep8 style guide to tell you what is wrong with your code based on the codes that come back from running pylint

Challenge​

Challenge trainees to fix all the pylint errors in their code. They should focus on solving one issue at a time, and understanding why pylint thinks it is a problem.

Grant them ~5 minutes to get the highest pylint score they can.

Discuss: is the code now perfect? Has pylint fixed everything?

Explain that following the style guide is important, but not sufficient. Code with a low pylint score will be low quality, but code with a high pylint score will not necessarily be high quality.

Effective Tool Use​

State that trainees will be using their devices a lot, both during the course and for the next several decades after that.

Assert that if you spend that much time with any tool, you should learn how to use it effectively.

Get trainees to share the VSCode and terminal shortcuts they researched in the pre-work.

Discuss VSCode shortcuts and commands with trainees, demonstrating each one as they mention it.

Ensure that the following are covered:

VSCode​

  • cmd + Click to jump to definitions
  • 'Rename Symbol' to rename variables
  • tab and shift+tab to indent or outdent lines in bulk
  • cmd+/ to comment out lines in bulk
  • option to select multiple places at once

Terminal​

  • Use tab to auto-complete
  • Use up arrow to get previous commands
  • Use ctrl + c to cancel a command
  • Use ctrl + l to clear the terminal
  • Use ctrl + a to go to the start of the line
  • Use ctrl + e to go to the end of the line

Good Habits​

Identify following the style guide and using shortcuts effectively are good habits that will help them throughout their careers.

Name regular commits as another such habit.

Explain that you should commit often. Every 10-20 minutes is ideal. This will help you to keep track of your changes and make it easier to revert if you need to.

Get trainees to commit their latest pylinted code as practice.

Mention, briefly, that regularly running tests is another excellent habit

Avoiding Clutter​

Highlight that all of these habits have a common theme; they're about reducing effort and mental load so you can focus on what's important while being confident that the fundamentals are secure.

Explain that perhaps the most important lesson any developer can learn is to focus on one thing at a time.

State that multitasking is not really a thing; it's actually just switching attention rapidly, and it harms focus/productivity unless carefully managed.

Explain that you should close all your tabs/programs unless you are actively working with them.

Stress that time spent searching for something in a forest of windows, and time spent switching tasks, is lost productivity.

Introduce YAGNI (You Ain't Gonna Need It). Following this principle will help trainees focus on the task at hand.

Explain that this goes for VSCode as well. Have only one instance open at a time. Close all your tabs. You Ain't Gonna Need It.

Challenge​

Challenge trainees to declutter their machines:

  • Remove taskbar items
  • Close browser tabs
  • Turn off login items (programs that start at startup)
  • Install an ad blocker
  • Organise files/folders