What is Comments in Python - Types, How to Write, Uses

Comments in Python

Have you looked at your own code after a week and wondered, 'What was I even thinking here?' If yes, then comments in Python are about to become your new helper. Comments are like those helpful sticky notes you leave for future-you (or anyone else reading your code). They're perfect for explaining tricky logic, marking areas to revisit, or just making your code easier to follow.

In this Python Tutorial, let's explore comments in Python, including types of comments in Python, how to write good comments in Python, use of Python comment, and a lot more. Additionally, enrolling in Python for Data Science and AI Certification can help you enhance your Python skills and apply them effectively in data science and AI projects.

What are Comments in Python?

Comments in Python are notes written in code to explain what the code does, but the computer ignores them when running the program. They start with a # symbol and are helpful for making the code easier for yourself and others to understand.

Syntax for Creating a Comment

#This is a comment
print("Welcome to Scholarhat!")

Types of Comments in Python

There are three types of comments in the Python programming language, those are:

1. Single-line Comments
2. Multiple line comments in Python
3. Docstring Comments

1. Single line Comment in Python

• A single-line comment in Python begins with the hashtag (#) and continues to the end of the line.
• If the comment is multiple lines, place a hashtag on the next line and continue with the Python Comments.
• Single-line comments in Python have proven beneficial for providing quick explanations for Variables in Python, Function Declarations in Python, and expressions.

Example of Single Line Comment in Python

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

This Python code in the Python Compiler outputs "Hello, World!" to the console and contains a single-line comment denoted by the "#" symbol, which is used to add explanations or comments to the code but is disregarded when the code is executed.

Output

Hello, World!

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2. Multiple line Comments in Python

Multiline comments are not supported in Python. However, there are other methods for writing multiline comments.

Using multiple hashtags (#) in multiline comments

Example of Multiple Line Comment in Python

        '''
This is a multiline
comment.
'''
print ("Hello, World!")

This Python code in the Python Editor includes a multiline comment encased in triple single quotes and acts as an explanation or documentation block while simultaneously being ignored during execution. The message "Hello, World!" is then printed to the console.

Output

Hello, World!

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3. Using Python's string literals

• Python String literals, which can be used with triple quotes, either ''' or ", are another method for implementing this.
• For multi-line strings, these triple quotes are typically utilized. However, we can use it as a comment if we don't assign it to any variables or functions.
• If a string is not allocated to any Python Function or Python Variable, the Python interpreter ignores it.

Example of Using String Literals as Comments

'''
This is a multi-line string literal.
It looks like a comment but is stored in memory.
Avoid using it as a comment unless it's part of a docstring.
'''
print("Hello, Python!")

4. Docstring in Python

• Docstrings are a built-in feature of Python that allows you to remark on modules, methods, functions, objects, and classes.
• Three quotes (''' or " ") are used to write them in the first line following the definition of a module in Python, function, method, etc.
• The interpreter will not recognize it as a docstring if you do not use it in the first line.
• Additionally, you can use the __doc__ attribute to retrieve docstrings.

Example of Docstring in Python

        def greet(name):
    """Greets the specified person."""
    print(f"Hello, {name}!")
greet("Ram")

The greet function in this code has a single parameter, name. Using f-strings, the greet function prints a customized greeting on the terminal.

Output

Hello, Ram!

How to Write Good Comments in Python?

To write good comments in Python, we provide you with some suggestions please follow them:

• Please make sure comments are concise.
• Avoid making generic comments; only include them if they provide more context.
• Write comments that, rather than focusing on specifics, highlight the general goal of a function or method.
• Excellent comments are self-explanatory.
• Avoid making repeated comments.

Use of Python Comment

1. Make the code simpler to comprehend:

• Coding comments will make it simpler to refer to in the future.
• Additionally, the code will be simpler for other developers to grasp.

2. Using Comments to Help with Debugging:

• Instead of eliminating the line of code that results in the error if we encounter one when executing the program, we can remark it.

Best Practices for Writing Comments

Here are several best practices for writing comments that are:

1. Keep Comments Relevant and Concise:

Example

# Check if the user input is valid
if user_input.isdigit():
    print("Valid input")

2. Use Proper Grammar and Punctuation:

Example

# Calculate the area of a circle
radius = 5
area = 3.14 * radius ** 2

3. Avoid Redundant Comments:

Bad Example:

# Increment the value of x by 1
x = x + 1

Better Example:

# Adjust x to account for one additional item
x = x + 1

4. Update Comments as Code Changes:

Example

# This function multiplies two numbers
def calculate(a, b):
    return a + b  # The comment should reflect the addition, not multiplication

5. Avoid Excessive Comments:

Example

# Initialize a list with even numbers
even_numbers = [2, 4, 6, 8, 10]

6. Use TODO Comments for Pending Tasks:

Example

# TODO: Optimize this loop for large datasets
for i in range(1000):
    print(i)

By following these practices, your comments will be meaningful, helpful, and maintainable!

Advantages of Using Comments in Python

Python comments offer several advantages. Their main advantages are:

• Comments in Python help others quickly understand the purpose and functionality of your code.
• They explain complex logic in the code, making it easier to follow and interpret.
• Comments in Python simplify debugging by providing clarity on what each part of the code is supposed to do.
• They improve the readability of the code, especially for developers reviewing it later.
• Comments in Python act as reminders for developers, helping them recall why certain decisions were made in the code.
• They are essential for helping new developers understand the project without extensive explanations.

Summary

Python comments are very important. They help to explain what is going on in a program and can be used to prevent errors from happening. When you use comments, it is important to keep them up to date so that they accurately reflect the code. If you prefer a structured learning approach, you may also consider Python certification, which provides comprehensive guidance and resources to help you master the language.

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