Day 5 of 30: ✏️ Code Style & Best Practices

Learn how to write clean, readable Python code and catch simple errors!

May 05, 2025

🔄 Quick Recap (Day 4)

You learned about variables and data types (int, float, str, bool).
You practiced checking types and converting between them.

🎯 What You’ll Learn Today

Why consistent naming and formatting matter.
Basic naming conventions for variables and functions.
How to spot and fix simple syntax errors.

📖 Why Code Style Matters

Just like neat handwriting makes a school notebook easier to read, consistent code style helps anyone (including future you) understand your programs quickly:

Readability: Well-organized code is easier to follow and maintain.
Collaboration: When many people work on code, everyone follows the same conventions.
Debugging: Clean code helps spot mistakes faster.

Python’s official style guide, PEP 8, recommends using:

snake_case for variable and function names (lowercase with underscores).
4 spaces for indentation, not tabs.
Line length limited to ~79 characters so lines don’t wrap awkwardly.

📖 Naming Conventions

Variables & functions: user_age, calculate_total()
Constants (values that don’t change): PI = 3.14, MAX_RETRIES = 5
Classes (later lessons): MyClass (CamelCase)

Example:

# bad style
X=42
def f(x):return x*2

# good style following PEP 8
user_age = 42

def double(number):
    return number * 2

Notice spaces around = and around operators.

📖 Spotting Syntax Errors

Python will show an error if it can’t understand your code. Common mistakes include:

Missing colon : after if, for, def.
Mismatched quotes or parentheses.
Indentation problems (mixing spaces and tabs).

Example error:

  File "example.py", line 2
    print("Hello World!)
                       ^
SyntaxError: EOL while scanning string literal

This means you started a string with " but forgot to close it before the end of the line.

🧙‍♂️ Take the Wand and Try Yourself

Create a new file style_test.py.
Inside, write two functions with bad style (no spaces, odd names), for example:
```
def addNumbers(a,b):return a+b
result=addNumbers(2,3)
print(result)
```
Run python style_test.py to confirm it works.
Now refactor your code following PEP 8:
- Rename to snake_case.
- Add spaces around operators and after commas.
- Separate function definition and call onto separate lines.

Solution Example (style_test.py):

# style_test.py: improved style

def add_numbers(a, b):
    return a + b

result = add_numbers(2, 3)
print(result)

Expected output:

Run:

python style_test.py

Once you see the correct output and your code looks tidy, you’re mastering code style!

On Day 6, we’ll explore conditional logic with if statements—see you there!

Day 5 of 30: ✏️ Code Style & Best Practices

Subscribe to keep reading

Keep Reading

Digital Mago