Last updated 2024-05-13 08:45:09

What Is A Docstring?

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What is a Docstring?

Documentation string or Docstring is a form of in-code documentation similar to comments with the difference being that its usually more structured and usually found in specifically defined parts of the codebase.

Docstring structure

Docstring are mostly used to describe a specific segment of code, typically a module, class [→], method [→], or function [→]. Unlike standard code comments [→], which are meant for casual annotations, docstrings are more structured and can often be processed by documentation generation tools to create external documentation automatically.

Docstrings adopt the syntax designated for writing comments in the programming language being used.

Where are Docstrings Used?

Docstrings are embedded directly in the code, at the start of a code block that defines a module, function, class, or method. They explain the purpose and behavior of the code block without requiring a developer to read and understand the code itself. This is useful for quick insights, especially in large or complex projects.

Example of Docstring Usage

Here’s a conceptual example of how a docstring might appear:

01: /** 02: * Calculates the sum of two numbers. 03: * 04: * Parameters: 05: * a (Number) - The first number. 06: * b (Number) - The second number. 07: * 08: * Returns: 09: * Number - The sum of the two numbers. 10: */ 11: function addNumbers(a, b) { 12: return a + b; 13: }

This example illustrates a generic way docstrings might be formatted to provide clear information about function parameters and return values.This particular example describes both the parameters expected by the function and what it returns including the expected and returned types respectively.

Benefits of Using Docstrings

  • Documentation: Docstrings provide a concise description of what a block of code does next to the code itself, making updates and maintenance easier.
  • Tool Integration: Many programming languages have tools that can extract docstrings to generate comprehensive external documentation.
  • Developer Onboarding: New team members can quickly get up to speed by reading the docstrings to understand how and why parts of the system work.

Best Practices for Writing Docstrings

To make the most out of docstrings, consider adhering to these best practices:

  • Consistency: Use a consistent format for all your docstrings. This may include a description, parameter lists, return values, and exception details.
  • Clarity: Keep the language simple and direct to ensure that the purpose and functionality are easy to understand.
  • Completeness: Aim to cover all essential aspects of the code functionality in your docstrings, including any side effects or dependencies.


Docstrings are a vital part of effective code documentation practices. If used properly Docstrings can be a better alternative to generic comments since they are more structured.

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