What Are Comments in Python?

Comments in Python are human-readable annotations that explain and clarify how the code works. They are ignored by the Python interpreter when the program runs, making them valuable tools for documentation, collaboration, debugging, and code maintenance. 

Why Use Comments?

Comments enhance the understandability of your code by providing context or explanations that might not be immediately obvious from the code itself. They are especially helpful when:

  • Displaying the purpose of logic or algorithms

  • Communicating reasoning behind decisions

  • Making code easier for others (or your future self) to read

  • Temporarily disabling code during testing

  • Improving collaboration in team projects ([turn0search7][turn0search1])

Comments do not affect program execution; they simply aid readability.

Types of Comments in Python

1. Single-Line Comments

Single-line comments start with the hash symbol (#). Everything after # on that line is ignored by Python.

Python does not execute comments; they exist solely for documentation. 

2. Inline Comments

Inline comments appear on the same line as code. Use them sparingly to clarify complex or non-intuitive statements.

Inline comments should be separated from code by at least two spaces for readability, as recommended in Python style guidelines. 

3. Multi-Line Comments

Python doesn’t have a specific syntax for multi-line comments like some other languages. There are two common approaches:

a) Multiple # Lines

You can stack single-line comments:

b) Triple-Quoted Strings

Triple-quoted strings ("""...""" or '''...''') can act like comments when not assigned to any variable. Python will ignore them at runtime, although technically they are string literals.

4. Docstrings

Docstrings are special triple-quoted strings placed right after module, class, or function definitions. They serve as built-in documentation that can be extracted by tools and are stored in the object’s __doc__ attribute.
Example:

  • Best Practices for Writing Comments

  • Be Clear and Concise: Comments should explain why something is done, not what the code does. (Well-written code typically explains the what.) 

  • Use Comments Purposefully: Avoid redundant comments that repeat obvious code

  • Update Comments with Code: Keep comments in sync with code changes to avoid confusion.

  • Separate Comments from Code: Use spaces and formatting to make comments readable. (PEP 8 recommends separating inline comments from code with two spaces before #.)

  • Prefer Docstrings for Public APIs: Use docstrings to document functions, classes, and modules.