2 5 1 Single-line Comments Explained

Key Concepts

Single-line comments in Python are used to add explanatory notes or annotations within the code. They are not executed by the Python interpreter and are solely for the benefit of the programmer. The key concept is:

Using the hash symbol (#) to create single-line comments.

1. Using the Hash Symbol (`#`) for Single-line Comments

In Python, any text following the hash symbol (#) on the same line is considered a comment and is ignored by the interpreter. This allows you to add notes, explanations, or reminders directly in your code.

Example:

# This is a single-line comment
print("Hello, World!")  # This comment explains the purpose of the print statement

Think of the hash symbol as a marker that tells the interpreter, "Ignore everything after me on this line."

2. Practical Examples

Single-line comments are useful for various purposes, such as explaining the purpose of a block of code, providing context, or temporarily disabling a line of code.

Example: Explaining Code Purpose

# Calculate the area of a rectangle
length = 10  # Length of the rectangle
width = 5  # Width of the rectangle
area = length * width  # Calculate the area
print("The area is:", area)  # Output the result

Example: Temporarily Disabling Code

# Uncomment the following line to enable debugging output
# print("Debugging information: ", debug_info)

In this example, the line with the print statement is commented out, effectively disabling it. This is useful for debugging or testing purposes.

3. Best Practices

When using single-line comments, it's important to follow best practices to ensure your code remains readable and maintainable.

Keep comments concise and to the point.
Use comments to explain why something is done, not just what is done.
Avoid over-commenting, as it can clutter the code and make it harder to read.

Example: Good Commenting Practice

# Calculate the factorial of a number using recursion
def factorial(n):
    if n == 0:
        return 1  # Base case: factorial of 0 is 1
    else:
        return n * factorial(n - 1)  # Recursive case: n * factorial of (n-1)

In this example, the comments explain the logic behind the recursive function, making it easier for others (or yourself) to understand the code later.

Conclusion