Python Comments

In the world of programming, communication is key. And while most of that communication happens between a programmer and a computer, there’s another dialogue that’s equally important: the one between programmers. That’s where Python comments come in.

Python comments are lines in your code that Python interpreter ignores. They’re written for humans, not machines, to read. They’re the notes, explanations, and asides that you leave in your code to help others understand what you’re doing (and often, to remind your future self). In this article, we’ll explore the ins and outs of Python comments, from the basic syntax to best practices and beyond.

Python Comments Syntax

Python supports two types of comments: single-line and multi-line.

Single-line Comments

Single-line comments in Python begin with the hash symbol (#). Anything following the # on that line is part of the comment. For example:

# This is a single-line comment in Python
print("Hello, World!")  # This is an inline comment
Python

Multi-line Comments

Python does not have a specific syntax for multi-line comments. However, programmers use triple quotes (''' or """) to create multi-line comments, even though they are technically strings. Python will ignore string literals that are not assigned to a variable.

'''
This is a multi-line comment in Python
You can write as many lines as you want
'''
print("Hello, World!")
Python

Python Comments Best Practices

Comments are a crucial part of your code, but they can also become a crutch or a source of confusion if not used properly. Here are some best practices for using comments in Python:

  1. Clarity over quantity: A few clear, concise comments are better than many vague or redundant ones. Your comments should explain why something is done, not what is being done. The code itself shows what is being done.
  2. Update your comments: Comments that don’t reflect what the code does can be more confusing than no comments at all. If you change your code, update your comments too.
  3. Avoid obvious comments: Comments should provide additional information not immediately apparent from the code itself. If the code is self-explanatory, it might not need a comment.
  4. Use comments for complex logic: If your code includes complex logic or workarounds for bugs, it’s helpful to leave a comment explaining what’s happening and why.

Python Comments for Functions (Docstrings)

In Python, comments can also take the form of documentation strings, or docstrings for short. Docstrings are multi-line comments used to explain the purpose of a function, method, class, or module. They’re enclosed in triple quotes and placed immediately after the definition of a function or class.

def add_numbers(a, b):
    '''
    This function adds two numbers and returns the result.
    Parameters:
    a (int): The first number
    b (int): The second number
    Returns:
    int: The sum of a and b
    '''
    return a + b
    
added_number = add_numbers(5,3)
print(added_number)
Python

Docstrings can be accessed using the __doc__ attribute of the function or class, or with the help() function, making them a useful tool for providing documentation.

Wrapping Up

Python comments are an essential tool for making your code understandable to others and your future self. Whether you’re explaining the purpose of a function with a docstring, leaving a note about a tricky bit of logic, or temporarily disabling a piece of code with a comment, understanding how to comment effectively is a crucial part of Python programming.

Frequently Asked Questions (FAQ)

  1. What are Python comments?

    Python comments are lines that are not executed by the Python interpreter. They are used to add notes or explain the code to make it more understandable for humans.

  2. How do I write a comment in Python?

    In Python, comments are written by starting the line with a hash symbol (#). Anything after the # on that line is considered a comment.

  3. Can I write multi-line comments in Python?

    Python does not have a specific syntax for multi-line comments. However, you can use triple quotes (''' or """) to create a multi-line string, and if this string is not assigned to a variable, Python will ignore it, effectively making it a multi-line comment.

  4. What are docstrings in Python?

    Docstrings, short for documentation strings, are a type of comment used in Python to explain the purpose of a function, method, class, or module. They’re enclosed in triple quotes and placed immediately after the definition of a function or class.

  5. Why should I comment my code?

    Comments make your code easier to understand for other people and for your future self. They can explain the purpose of a function, provide additional context, or clarify complex sections of code. However, comments should be used judiciously and should always be kept up-to-date with the code they describe.

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