Скачать или смотреть Best Practices for Writing Docstrings in Python Functions with Multiple Return Types

Discover the best PEP8 practices for documenting Python functions that return multiple types. Learn how to effectively communicate return values with practical examples and tips.
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Understanding PEP8 and Docstrings for Python Functions

When writing Python code, clarity is key. One important aspect of clarity is how we document our functions, especially when it comes to describing what they return. A frequent challenge developers face is how to properly document a function that returns values of different types. This article will guide you through the best practices for writing effective docstring documentation in line with PEP8 guidelines—particularly for functions with multiple return types.

The Problem: Documenting Functions with Multiple Return Types

Consider the following scenario: you create a function that operates based on a parameter and returns different values based on that parameter's value. Here’s a sample function illustrating this concept:

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In this case, when the eg parameter is greater than 2, the function returns a tuple of integers (2, 4). Conversely, if eg is 2 or less, it returns a tuple containing a string and None ('no', None). This duality in returned types can pose a challenge in documenting the function's expected returns properly.

The Solution: Documenting Different Return Types with PEP8

Option 1: Use Union Types (Python 3.10 and Above)

If you are working with Python 3.10 or later, you can take advantage of the | operator, which allows you to specify multiple accepted return types more succinctly. Here’s how you can redefine your function signature:

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In this signature, Tuple[int, int] | Tuple[str, None] clearly indicates that the function can return either a tuple of integers or a tuple containing a string and None. This makes it easy for the user to understand the possible outcomes of calling eg_fun().

Option 2: Use Union for Older Python Versions

If you’re still using a version prior to Python 3.10, you can achieve the same clarity by employing Union from the typing module:

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This signature defines that eg_fun() may return either of the specified tuples, preserving clarity for anyone reading your code.

Conclusion

Proper documentation is essential for making your code understandable and maintainable. When dealing with functions that return different value types, it’s crucial to use the correct type annotations in your function signature. By utilizing Union in older Python versions or the newly introduced | operator in Python 3.10 and above, you can effectively communicate what users of your function can expect.

With clear docstrings and accurate type annotations, you create a better experience for other developers who may work with your code. Whether you’re simply documenting your own functions or contributing to larger projects, following these PEP8 guidelines is key to ensuring clarity and effectiveness.

Remember, clear code is good code!