PEP 8 & Pythonic Style

Code is read much more often than it is written. PEP 8 (Python Enhancement Proposal #8) is the definitive style guide for Python. Adhering to PEP 8 is not just about aesthetics; it’s about making your code accessible to the millions of other Python developers worldwide.

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1. Key Structural Rules

Indentation & Spacing

• Use 4 Spaces: Never use Tabs.
• Maximum Line Length: 79 characters for code, 72 for docstrings.
• Blank Lines:
  • Two blank lines between top-level functions and classes.
  • One blank line between methods inside a class.

Imports

• Always put imports at the top of the file.
• Group them in this order:
  1. Standard library (e.g., os, sys).
  2. Related third-party imports (e.g., django, requests).
  3. Local application/library specific imports.

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2. Naming Conventions

Type	Convention	Example
Variable	snake_case	user_id
Function	snake_case	calculate_total()
Class	PascalCase	UserAccount
Constant	UPPER_CASE	MAX_RETRIES
Package/Module	lowercase	utils

Descriptive Names

Avoid generic names like data, item, or x. Use names that describe the purpose of the variable (e.g., pending_transactions).

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3. The Zen of Python (PEP 20)

Beyond formatting, Python has a philosophy. You can read it by running import this in your terminal.

• Beautiful is better than ugly.
• Explicit is better than implicit.
• Simple is better than complex.
• Readability counts.

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4. Modern Tooling: Ruff & Black

In a professional setting, you don’t manually check for PEP 8. You use automation.

Ruff (The Linter)

Ruff is an extremely fast Python linter that checks for hundreds of style and logic errors.

pip install ruff
ruff check .

Black (The Formatter)

Black is an “uncompromising” code formatter. It takes your code and completely rewrites it to follow PEP 8 perfectly.

pip install black
black my_script.py

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5. Summary Table

Feature	Guideline
Indentation	4 Spaces (No Tabs).
Naming	snake_case for everything except Classes.
Quotes	Use single or double consistently (Black prefers double).
Whitespace	Avoid extra spaces inside parentheses or before commas.

Consistency is King

The most important rule of PEP 8 is Consistency. If you are contributing to an existing project, follow its existing style even if it contradicts PEP 8.