Tutorial How to Comment in Python
Tutorial How to Comment in Python

Tutorial How to Comment in Python [ With Example ]

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Welcome to our tutorial on commenting in Python! As experienced programmers, we know the importance of writing clean and maintainable code that is easy to understand for ourselves and others. Commenting is an essential component of achieving this goal. In this tutorial, we will cover the various types of comments in Python, best practices, conventions, and provide examples to help you write effective comments in your Python code.

Whether you are a beginner just starting with Python or an experienced developer looking to improve your coding skills, this tutorial is for you. Let’s get started by understanding the different types of comments in Python.

Line Comments in Python

Line comments are the most common type of comment used in Python. They are used to describe individual lines of code and are usually placed at the end of the line, after the code. To create a line comment, you simply use the hash symbol (#) followed by your comment text.


x = 5  # this is a comment

You can also use line comments to comment out code that you don’t want to run. This can be useful during testing or debugging.


# x = 5  # this line of code will not run

It’s important to note that line comments only apply to the line of code that they are on. If you want to comment on multiple lines of code, you will need to use a different type of comment.

Block Comments in Python

Block comments are used when we want to add a comment that spans several lines of code. In Python, block comments are denoted by starting a line with a # followed by a whitespace, and then the comment text. We can use block comments for explaining the purpose of a function or class, or for providing information about a complex algorithm.


Here is an example of block comments:

# This function calculates the sum of two numbers
# Parameters:
#     num1 (int): The first number
#     num2 (int): The second number
# Returns:
#     int: The sum of num1 and num2

def add_numbers(num1, num2):
    return num1 + num2

As you can see, the block comments are used to provide information about the function. We have used the # symbol at the beginning of each line to indicate that it is a comment, and we have added a whitespace after the # symbol before writing the comment text. This makes it easier to read and distinguish between code and comments.

It’s important to note that block comments should not be used excessively. They can make the code harder to read if there are too many comments. Only use block comments when necessary to provide context or explanation for complex code.

Multiline Comments in Python

While line comments are useful for short explanations, sometimes you need to add more detailed information, which is where multiline comments come into play. As the name suggests, multiline comments can span across multiple lines and are enclosed within triple quotes.

How to Write Multiline Comments in Python

Writing a multiline comment is as simple as enclosing your text within triple quotes. Here is an example:

This is a multiline comment in Python.
It provides detailed information about the code
and can span across multiple lines.

In the above example, we use triple quotes to enclose our comment, which allows us to write multiple lines of text.

The Importance of Multiline Comments

When working on a larger project, it can be challenging to remember what each section of code does. Having detailed multiline comments can help you and other developers working on the project to understand the purpose of the code and how it works. It can also help to save time when making changes to the code by providing valuable context.

As with any comment, it’s critical to keep your multiline comments up to date and relevant. Avoid leaving outdated comments that no longer accurately describe the code or function.

Commenting Best Practices

Code comments are essential for making the code more understandable, maintainable, and scalable. However, writing comments can be time-consuming and, in some cases, may even cause confusion if not done correctly. In this section, we will discuss some of the best practices for commenting in Python.

Use Clear and Concise Language

When it comes to writing comments, clarity is key. Use clear and concise language that clearly conveys the purpose of the code. Avoid using technical jargon or abbreviations that may not be familiar to other developers. By keeping the language simple, you can ensure that your comments are easily understood by everyone who reads them.

Keep Comments Up-to-Date

Comments are not static; they need to be updated as the code evolves. Make sure to review your comments regularly and update them accordingly. Also, if there is a change in the functionality of the code, update the comments accordingly to ensure that they remain helpful to other developers.

Use Comments to Explain Why, Not What

It is essential to use comments to explain the purpose or intent of the code rather than describing what the code does. Code should be self-explanatory, and the comments should provide context for why the code exists. By focusing on the why, you can help other developers understand the rationale behind the code and make informed decisions when making changes.

Avoid Overcommenting

While commenting is critical, overcommenting can make your code cluttered and difficult to read. The comments should only be used where necessary and should not be used to state the obvious. Comments should be used sparingly, ensuring that they provide valuable information and not just repeat information that is already evident from the code itself.

Consistency is Key

Consistency is crucial when it comes to commenting. Adopting a consistent style across the codebase can help increase readability and make the code easier to understand. Make sure to agree on a commenting style with your team and stick to it. By doing so, the code will become more maintainable.

Use Tools to Automate Documentation

Automation tools such as Sphinx can help document your Python code automatically. These tools parse your code and generate documentation based on the comments embedded in the code. Using these tools can help you save time while ensuring that your code is well-documented.

Commenting Conventions and Guidelines

Commenting in Python is an essential practice that can make or break the readability and maintainability of the code. To ensure consistency and clarity in commenting, it is crucial to follow proper conventions and guidelines.

Use clear and concise language

Comments should be written in simple and understandable words. Avoid using technical jargon or colloquialisms that may confuse readers. Use precise language and try to convey the necessary information in a concise and straightforward manner.

Comment every function and method

It is essential to comment every function and method in your code. Comments should explain the purpose of the function or method and provide details on how it works, including any parameters and return values.

Use descriptive variable names

Using descriptive variable names can help reduce the need for comments. Variables that are named clearly and accurately often make the code self-explanatory. If you believe that a variable name needs to be explained, include a comment that describes its purpose.

Comment throughout the code

Comments should not only be written at the beginning of a code block. They should be added throughout the code to explain the functionality of every section. This practice makes it easier for others to understand what is happening at each step and can help with debugging.

Update comments when modifying code

When modifying code, don’t forget to update the comments to reflect the changes you’ve made. This practice ensures that the comments remain relevant and accurate, even as the code evolves over time.

Use commenting tools and plugins

There are several commenting tools and plugins available that you can use to automate the commenting process, making it quicker and easier to maintain code comments. Tools like Docstring Generator can help generate comments for functions and methods, while plugins like PyCharm can highlight lines of code that are missing comments.

Examples of Commenting in Python

Now that we’ve covered the basics of commenting in Python, let’s take a look at some examples of how comments can be used in actual code.

Example 1: Single Line Comment

The following code demonstrates how to add a single line comment using the ‘#’ character:

# This is a single line comment
print("Hello, World!")

The comment in this example is used to explain the purpose of the code, without affecting the output of the program.

Example 2: Block Comment

In the next example, we will see how to add a block comment using triple quotes:

This is a block comment that spans multiple lines.
We can use it to explain sections of code or to provide documentation.
print("Hello, World!")

Block comments are useful when you need to include a lot of information about a section of code.

Example 3: Multiline Comment

Here’s an example of how to add a multiline comment using several single line comments:

# This comment is part of a multiline comment
# that spans multiple lines
# We can use it to explain complex code
print("Hello, World!")

Multiline comments are useful when you want to add comments to multiple lines of code without using block comments.

Example 4: Commenting Best Practice

Finally, let’s take a look at an example of good commenting practice:

# This function calculates the sum of two numbers
# Input: x (int), y (int)
# Output: sum (int)
def add_numbers(x, y):
    # This variable holds the sum of the numbers
    sum = x + y
    return sum

In this example, the comments provide a clear explanation of what the function does, what input it requires, what output it produces and how it works. This makes the code easier to read and understand.

Remember, commenting is an essential part of writing clean, readable code. By following the best practices and guidelines we’ve covered in this article, you can make your code more maintainable and easier to understand for yourself and for other developers.


Now that we have covered the various types of comments in Python, you should be equipped with the knowledge to effectively comment your code. Remember to use line comments when you need to add a brief explanation to your code. Block comments are perfect for adding elaborate explanations to your code. When you have a large block of code that requires commenting, be sure to use multiline comments.

When it comes to commenting best practices, always keep your comments concise, relevant and up-to-date. Use appropriate commenting conventions and guidelines to make your code more readable and understandable to other developers. Lastly, don’t forget to use commenting examples to help you get started with commenting your code.

Final Thoughts

Commenting your Python code is an essential aspect of programming, particularly in a collaborative environment. We hope that this tutorial has provided you with a solid foundation to start commenting your Python code effectively. By implementing these techniques and best practices, you can improve your code readability, make it more understandable, and ultimately become a more efficient programmer.

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