PEP 8 Guidelines

Introduction

PEP 8 is the official style guide for Python code. It provides conventions for writing readable and consistent Python programs.

Following PEP 8 helps developers collaborate more effectively and maintain code quality across projects.

Readability counts.

What is PEP 8?

PEP 8 stands for Python Enhancement Proposal 8. It was created to standardize Python code formatting.

The guidelines cover naming conventions, indentation, line length, whitespace usage, comments, and more.

• Improves code readability
• Facilitates collaboration
• Reduces errors caused by inconsistent style

Key PEP 8 Guidelines

Below are some of the most important PEP 8 rules every Python developer should follow.

• Use 4 spaces per indentation level; never use tabs.
• Limit lines to 79 characters for code and 72 for comments.
• Separate top-level functions and classes with two blank lines.
• Use lowercase with underscores for function and variable names (snake_case).
• Use CapWords (PascalCase) for class names.
• Surround binary operators with a single space on both sides.
• Avoid extraneous whitespace inside parentheses, brackets, or braces.
• Write docstrings for all public modules, functions, classes, and methods.
• Use comments sparingly but effectively to explain why code exists.

Indentation and Line Length

Consistent indentation is crucial in Python since it defines code blocks.

PEP 8 recommends 4 spaces per indentation level and discourages mixing tabs and spaces.

Lines should be limited to 79 characters to improve readability on various devices.

• Use 4 spaces per indent level.
• Break long lines using Python's implied line continuation inside parentheses, brackets, and braces.
• If needed, use a backslash for explicit line continuation.

Naming Conventions

PEP 8 defines naming styles to distinguish different kinds of identifiers.

Following these conventions makes code easier to understand.

• Function and variable names: lowercase with words separated by underscores (snake_case).
• Class names: CapitalizedWords (PascalCase).
• Constants: all uppercase letters with underscores (UPPERCASE).
• Modules and packages: short, lowercase names without underscores.

Whitespace in Expressions and Statements

Proper use of whitespace improves code clarity.

PEP 8 specifies where to add or avoid spaces around operators and delimiters.

• Use spaces around binary operators like assignment (=), comparisons (==, <, >), and arithmetic (+, -, *, /).
• Do not use spaces immediately inside parentheses, brackets, or braces.
• Avoid extra spaces before commas, colons, and semicolons.

Comments and Docstrings

Comments explain why code exists and how it works, aiding future readers.

Docstrings provide documentation for modules, classes, and functions.

• Use complete sentences for comments, starting with a capital letter.
• Block comments generally apply to some code that follows and are indented to the same level.
• Inline comments should be separated by at least two spaces from the statement and start with a #.
• Use triple quotes for docstrings and describe the purpose, parameters, and return values.