Python Code Guidelines

Aug 08, 2021

Dec 20, 2023

3 minutes

pythonlanguagecodeguidelinescommunity

Adhering to these standards will help maintain consistency, readability, and best practices across our Python projects.

Table of Contents

• Table of Contents
• Naming Conventions
• Formatting
• Imports
• Whitespace and Indentation
• Comments
• Documentation
• Error Handling
• Function and Method Arguments
• String Formatting
• Virtual Environments

Naming Conventions

• Use snake_case for function and variable names.
• Use CamelCase for class names.
• Use UPPER_CASE for constants.

Formatting

• Use four spaces for indentation.
• Limit lines to 79 characters.
• Prefer spaces over tabs.

def example_function(arg1, arg2):
    if arg1 and arg2:
        print("Hello, world!")

Imports

• Import modules in separate lines.
• Use explicit imports over wildcard imports.
• Group imports in the following order: standard library, third-party libraries, local modules.

import os
import sys

from datetime import datetime
from flask import Flask, render_template

from my_project import utils

Whitespace and Indentation

• Avoid trailing whitespaces.
• Use blank lines to separate functions, classes, and blocks of code logically.

Comments

• Write comments to explain complex pieces of code or provide additional context.
• Avoid unnecessary comments that simply restate the code.

# This function adds two numbers together
def add_numbers(a, b):
    return a + b

Documentation

• Document all public functions, classes, and modules using docstrings.
• Use triple double-quotes for multiline docstrings.

def my_function(param1, param2):
    """
    This function does something awesome.

    Args:
        param1 (int): The first parameter.
        param2 (str): The second parameter.

    Returns:
        bool: True if successful, False otherwise.
    """
    # Function implementation here
    pass

Error Handling

• Use try, except blocks for handling exceptions.
• Avoid using a bare except clause; be specific about the exceptions you catch.

try:
    result = my_function()
except ValueError as e:
    print(f"An error occurred: {e}")

Function and Method Arguments

• Use meaningful names for function and method arguments.
• Avoid using mutable types (e.g., lists) as default argument values.

def process_data(data, threshold=10):
    # Function implementation
    pass

String Formatting

• Prefer f-strings for string formatting.

name = "John"
age = 30
print(f"My name is {name} and I am {age} years old.")

Virtual Environments

• Use virtual environments to manage dependencies for each project.

# Create a virtual environment
python -m venv venv

# Activate the virtual environment
source venv/bin/activate  # On Unix or MacOS
venv\Scripts\activate  # On Windows

These guidelines aim to ensure code consistency and readability, fostering a collaborative and efficient development environment. Happy coding in Python!