Comments in Python -Types, How to Write, Uses

Comments in Python are essential for making your code readable and maintainable. Comments help explain what your code does, making it easier for others (and your future self) to understand. In Python, you can use the # symbol for single-line comments and triple quotes (''' or """) for multi-line comments, although the latter is typically used for docstrings. A comment in Python is used to annotate code for better understanding.

In this Python Tutorial, we explore comments in Python, including types of comments in Python, how to write good comments in Python, use of Python comments, and a lot more. Whether you're a beginner or an experienced programmer, using comments correctly will improve your coding efficiency. 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. Developers use comments in Python to explain complex logic in their programs. A comment in Python starts with the # symbol and extends to the end of the line.

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. The comment in Python feature allows programmers to disable specific lines of code without deleting them. A comment in Python does not affect the execution of the program. You can use a comment in Python to document functions, variables, and important code sections.

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, Scholarhat!") 

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, Scholarhat!

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, Scholarhat!")

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!

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, Scholarhat!")

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 of Python, 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("Scholarhat")

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.
• Using a comment in Python effectively makes debugging and collaboration easier.

What Are Comments in Python Used For?

In Python, comments start with a hash symbol (#) and continue until the end of the line. However, hash characters in a string are not regarded as comments. There are three methods to create a comment: as a separate line, next to the relevant code statement, or as a multi-line comment block.

Python comments are useful in many ways, including these key purposes:

• Enhancing code readability
• Clarifying code for others
• Making it easier to understand after a long time
• Adding references or resources
• Facilitating code reuse

Why Are Comments Important in Python?

Comments are important in Python because they improve code readability and help in understanding the logic behind the code. They make programming more efficient and collaborative.

• Documentation: Comments explain the purpose of functions, classes, or code sections, helping understand complex logic.
• Readability: Well-commented code is easier to read, making it simple to understand even after a long time
• Debugging: Comments help in finding and fixing bugs by allowing parts of the code to be temporarily disabled
• Collaboration:I n teamwork, comments make code easier to share and review, improving teamwork and project flow.

Prevent Executing Code Using Comments

Docstrings vs. Comments in Python

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:

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.

Test your skills by following MCQs

Dear learners, attempt these MCQ questions and know your abilities.

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