Welcome to the exciting world of Python! As you begin your coding journey, you'll quickly realize that writing code is only half the battle. The other, equally important half, is making sure your code is understandable to yourself and others. This is where comments and docstrings come into play. They act as annotations within your code, providing explanations and context. Think of them as helpful notes left for future you or your collaborators.
Comments are lines of text within your Python script that are ignored by the Python interpreter. They are solely for human readers. In Python, there are two primary ways to add comments:
- Single-line comments: These start with a hash symbol (
#) and continue to the end of the line. They are perfect for brief explanations of a specific line or block of code.
# This is a single-line comment
print('Hello, Python!') # This comment explains the print statement- Multi-line comments (or block comments): While Python doesn't have a dedicated syntax for multi-line comments like some other languages (e.g.,
/* ... */), you can achieve the same effect by using multiple single-line comments.
# This is the first line of a multi-line comment.
# This is the second line.
# And this is the third.
message = "Learning about comments!"
print(message)It's important to use comments judiciously. Avoid commenting on obvious code. Instead, use comments to explain why you're doing something, or to highlight a complex piece of logic. Good comments clarify intent and complexity, not redundancy.
Docstrings (documentation strings) are special types of comments that are used to document Python functions, classes, modules, and methods. They are enclosed in triple quotes (either '''Docstring goes here''' or """Docstring goes here"""). Unlike regular comments, docstrings are accessible at runtime through the __doc__ attribute. This allows tools like IDEs and documentation generators to extract and display this information.
A good docstring typically includes:
- A concise summary line explaining what the function/class/module does.
- A more detailed explanation if necessary.
- Descriptions of arguments (parameters).
- A description of what the function returns (if anything).
- Any exceptions that might be raised.
def greet(name):
"""This function greets the person passed in as a parameter.
Args:
name (str): The name of the person to greet.
Returns:
str: A greeting message.
"""
return f"Hello, {name}!"
print(greet("Alice"))
print(greet.__doc__)When you run the code above, you'll see the greeting printed, and then you'll see the docstring itself printed. This demonstrates how docstrings are accessible. Documenting your code with docstrings is a crucial step in writing professional and maintainable Python programs.
graph TD
A[Start Writing Code] --> B{Need to Explain Code?}
B -- Yes --> C[Use Comments (#)]
B -- Yes --> D[Use Docstrings (''' or """)]
C --> E[Code is More Readable]
D --> E
E --> F[End]
By mastering the art of commenting and docstring usage, you'll significantly improve the quality and maintainability of your Python projects, making your coding journey smoother and more collaborative.