In Python, comments refer to the sections of the source code that the interpreter disregards when executing the program. These annotations or explanations, intended for programmers, are incorporated into the code to enhance human comprehension. Comments play a crucial role in enhancing code readability, aiding in the debugging process, and providing documentation for developers who may work on the code in the future.
Let us explore a straightforward example that demonstrates the functionality of comments in Python.
Example
# this is a simple comment
print("Welcome to our tutorial to learn Python")
Output:
Welcome to our tutorial to learn Python
Explanation:
In this instance, a comment has been introduced utilizing the hash '#' symbol. Additionally, we observe that the Python interpreter has disregarded the commented section throughout the program's execution.
Types of Comments in Python
There are primarily three types of comments used in Python, such as:
- Single-line Comments
- Multi-line Comments
- Docstrings
Let’s explore these categories by utilizing some examples:
1. Python Single-line Comments
In Python, a comment that occupies a single line begins with the hash '#' character, which Python disregards during execution. These single-line comments serve the purpose of offering brief clarifications or annotations regarding the code.
Let's examine a basic illustration of single-line comments in Python.
Example
# example of single-line comment
# this is a single-line comment
print("Welcome to our tutorial!")
Output:
Welcome to our tutorial!
Explanation:
In the example provided, a single-line comment has been incorporated using the hash '#' symbol. Consequently, the Python interpreter disregarded this specific line of code and proceeded to execute the following line, which is responsible for printing a statement.
Inline Comments
An inline comment refers to a specific kind of single-line comment that exists on the same line as a code statement, serving the purpose of clarifying a particular portion of that line.
Here is an example of inline comments in Python.
Example
# example of inline comment
print("Welcome to our tutorial!") # this is an inline comment
Output:
Welcome to our tutorial!
Explanation:
In the preceding illustration, an inline comment has been included utilizing the hash '#' symbol following the print function. The Python interpreter has disregarded the commented portion from that line of code.
2. Python Multi-line Comments
In contrast to other programming languages such as C, C++, and Java, Python lacks a specific syntax for creating multi-line comments.
Nonetheless, an analogous outcome can be attained through the methods listed below:
Multiple Single-Line Comments
A fundamental method for incorporating multi-line comments into your source code is by placing single-line comments consecutively, utilizing the hash symbol '#' at the beginning of each line.
Consider the subsequent example for crafting multi-line comments utilizing several hash symbols:
Example
# example of multiline comment
# this is a
# multi-line comment
# added to the code
# by stacking multiple
# single line comments
print("Welcome to our tutorial!")
Output:
Welcome to our tutorial!
Explanation:
In this instance, several individual single-line comments are aligned in succession to create the appearance of a multi-line comment.
Using Triple Quoted Strings
In Python, it is possible to emulate multi-line comments by utilizing triple-quoted strings (either ''' or """). Although these constructs are officially classified as multi-line strings, they can effectively serve the purpose of comments.
Below is a straightforward illustration demonstrating how to incorporate multi-line comments into your code by utilizing triple-quoted strings.
Example
# example of multiline comment
'''This is a
multi-line comment
added to the code
using the triple
quoted string
'''
print("Welcome to our tutorial!")
Output:
Welcome to our tutorial!
Explanation:
While triple quotes are not formally classified as comments, in the example provided above, we have employed them in a manner similar to comments for the purpose of making quick annotations or facilitating debugging.
3. Python Docstrings
Docstrings, which stands for documentation strings, are unique multi-line strings in Python that we can use to provide documentation for functions, classes, methods, and modules.
In contrast to standard comments, docstrings are retained during runtime. They can be accessed through the built-in help function or by utilizing the doc attribute. This characteristic renders them exceptionally valuable for creating well-documented and maintainable code.
Below is a brief illustration to clarify how docstrings operate in Python.
Example
# example of docstring
# defining a function
def welcome(name):
'''
This function prints a
welcome message for the user
'''
print(f'Hello, {name}!, Welcome to our tutorial.')
# calling the function
welcome('John')
# using the __doc__ attribute to access the docstring
print("Docstring:", welcome.__doc__)
Output:
Hello, John!, Welcome to our tutorial.
Docstring:
This function prints a
welcome message for the user
Explanation:
In this context, the documentation string is retained in memory throughout the execution of the program. When we access the doc attribute, it retrieves and returns the documentation string that has been stored.
Best Practices to Write Comments
The following are some tips one can follow in order to make their comments effective:
- The code should be self-explanatory. It is recommended to write comments to explain why something is done a certain way.
- Always keep the comments concise, to the point, and easy to scan.
- Outdated comments can be misleading and harmful. Therefore, it is a good practice to update or remove comments if any changes are made to the code.
- Use proper grammar and capitalization to keep the comments more professional and easier to read.
- PEP 8 suggests that inline comments should have at least two spaces before the hash '#' symbol. Therefore, it is recommended to follow the PEP 8 spacing rule.
Conclusion
In Python, the ability to comment effectively is an essential competency, as it significantly improves the clarity and upkeep of the code. Regardless of whether we are crafting a straightforward script or constructing an intricate application, well-defined and pertinent comments contribute to making the code appear more polished and comprehensible. This tutorial has covered the process of incorporating comments into Python programs. Additionally, we explored the various categories of comments available in Python, supported by a range of examples.
Python Comments - FAQs
1. How to write a comment in Python?
A comment can be created by utilizing the hash '#' symbol, as demonstrated in the following example:
Syntax:
# This is a comment
The Python interpreter disregards any content on that line that follows the hash '#' symbol.
2. What is the difference between a comment and a docstring?
- Comment: Comments are added to the code using the hash '#' symbol. The comments are ignored by Python and not stored in memory.
- Docstring: Docstrings are added to the code using triple quotes (''' or """) stored as metadata. We can access docstrings using help or doc.
3. Can we write multiline comments in Python?
Python lacks a formal syntax for multiline comments; nevertheless, we can achieve this by:
- Utilizing the # symbol across several lines
- Employing triple-quoted strings (either ''' or """)
4. Do comments affect Python code performance?
The Python interpreter entirely disregards comments, meaning they do not influence the execution speed or memory consumption (with the exception of instances where triple-quoted strings are utilized outside of docstrings).
5. Are comments required in Python programs?
While not a technical requirement, it is strongly advised to incorporate comments within Python code. Well-crafted comments enhance the readability of the code, facilitate maintenance, and simplify the debugging process.