In this tutorial, let us understand how to comment out a block of code in Python. As a developer working on a project for a US-based company, I recently encountered a situation where I needed to temporarily disable a section of my Python script without deleting it entirely. That’s when I discovered the power of commenting out code blocks in Python. Let us see how it works.
Comment Out Code
Commenting out code means temporarily disabling a portion of your script by turning it into a comment. This is useful when you want to test different variations of your code, troubleshoot issues, or simply save a block of code for later.
Read Interfaces in Python
Single-Line Comments in Python
In Python, you can create single-line comments by prefixing a line with the hash symbol (#). Here’s an example:
# This is a single-line comment
print("Hello, John from New York!")In this case, the line # This is a single-line comment is ignored by the Python interpreter, and only the print statement is executed.
Read Access Modifiers in Python
Comment Out a Block of Code in Python
When you need to comment out multiple lines of code in Python, you have a couple of options:
- Prefixing each line with the hash symbol (
#) - Using triple quotes (
"""or''') to create a multi-line comment
Method 1: Prefix Each Line with Hash (#)
One way to comment out a block of code is to prefix each line with the hash symbol (#).
Here’s an example:
# def greet(name):
# print(f"Hello, {name}!")
#
# greet("Sarah from California")I have shown you how will a commented line look in the below screenshot.
In this case, the entire function definition and function call are commented out.
Method 2: Use Triple Quotes (""" or ''')
Another approach is to use triple quotes (""" or ''') to create a multi-line comment. Here’s an example:
"""
def calculate_total(prices):
total = sum(prices)
return total
cart_prices = [10.99, 5.99, 8.49]
total_price = calculate_total(cart_prices)
print(f"The total price is: ${total_price:.2f}")
"""I have shown you how will a commented line look in the below screenshot.
In this example, the entire block of code, including the function definition, variable assignments, and print statement is commented out using triple quotes.
Read How to Use Single and Double Quotes in Python?
Keyboard Shortcuts to Comment Out Code in Python
Most IDEs and text editors provide keyboard shortcuts to quickly comment out a block of code. Here are a few common shortcuts:
- Windows/Linux:
Ctrl + / - macOS:
Cmd + /
By selecting the lines you want to comment out and using these shortcuts, you can easily comment the lines.
Read Python 3 vs Python 2 [Key Differences]
Best Practices to Comment Out Code in Python
When commenting out code, keep the following best practices in mind:
- Use meaningful comments to explain why you’ve commented out a specific block of code.
- Avoid leaving commented-out code in your final production script. Remove unnecessary comments before deploying your code.
- If you need to save a block of code for later use, consider moving it to a separate file or version control system instead of leaving it commented out in your main script.
Read Difference Between “is None” and “== None” in Python
Example
Let’s say you’re working on a Python script that generates reports for a US-based e-commerce company. You have a function that calculates the sales tax based on the state, but you want to temporarily disable it for testing purposes. Here’s how you can comment out the relevant block of code:
def calculate_order_total(subtotal, state):
# if state == "CA":
# tax_rate = 0.0725
# elif state == "NY":
# tax_rate = 0.08875
# else:
# tax_rate = 0.0
#
# tax = subtotal * tax_rate
# total = subtotal + tax
total = subtotal # Temporarily disable tax calculation
return total
order_subtotal = 149.99
customer_state = "CA"
order_total = calculate_order_total(order_subtotal, customer_state)
print(f"Order total: ${order_total:.2f}")In this example, the tax calculation logic is commented out using the hash symbol (#), and a temporary line total = subtotal is added to calculate the order total without taxes. This allows you to test the rest of the script without the tax calculation.
Conclusion
In this tutorial, I have explained how to comment out a block of code in Python which allows you to temporarily disable portions or save code for later use. By using single-line comments (#) or multi-line comments (""" or '''). I explained shortcuts for commenting out code in Python, some best practices for comment code, and also a real-world example.
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I am Bijay Kumar, a Microsoft MVP in SharePoint. Apart from SharePoint, I started working on Python, Machine learning, and artificial intelligence for the last 5 years. During this time I got expertise in various Python libraries also like Tkinter, Pandas, NumPy, Turtle, Django, Matplotlib, Tensorflow, Scipy, Scikit-Learn, etc… for various clients in the United States, Canada, the United Kingdom, Australia, New Zealand, etc. Check out my profile.
