How to Comment in Python: Simple Syntax and Examples

In Python, you write a single-line comment by starting the line with #. For multi-line comments, use triple quotes ''' or """ to enclose the comment block.

Syntax

Python supports two main ways to write comments:

• Single-line comment: Start the line with #. Everything after # on that line is ignored by Python.
• Multi-line comment: Use triple single quotes ''' or triple double quotes """ to enclose a block of text. This is often used for longer comments or documentation.

python

# This is a single-line comment

'''
This is a multi-line comment.
It can span multiple lines.
'''

Example

This example shows both single-line and multi-line comments in a Python program. Comments do not affect the program's output.

python

# This function adds two numbers

def add(a, b):
    '''
    This function takes two numbers
    and returns their sum.
    '''
    return a + b

result = add(3, 5)
print(result)  # Output the result

Output

8

Common Pitfalls

Some common mistakes when commenting in Python include:

• Forgetting the # for single-line comments, which causes Python to treat the text as code and raise errors.
• Using triple quotes for multi-line comments but placing them where Python expects code, which can create unintended string literals.
• Using comments to explain obvious code, which can clutter the code instead of helping.

python

# Wrong: missing # causes error
# print("Hello")  # Correct way

# Wrong: triple quotes used as comment but assigned or misplaced
text = '''This is a string, not a comment'''

# Right: use triple quotes only for actual multi-line comments or docstrings

Quick Reference

Comment Type	Syntax	Use Case
Single-line comment	# comment text	Brief notes or explanations on one line
Multi-line comment	''' comment text ''' or """ comment text """	Longer explanations or documentation blocks

Key Takeaways

Use # to write single-line comments in Python.

Use triple quotes ''' or """ for multi-line comments or docstrings.

Comments help explain code but should not state the obvious.

Incorrect comment syntax can cause errors or unintended behavior.

Multi-line comments are often used for function or module documentation.