Comments are descriptions that help programmers better understand the intent and functionality of the program.
They are completely ignored by the Python interpreter.
Advantages of Using Comments
Using comments in programs makes our code more understandable. It makes the program more readable which helps us remember why certain blocks of code were written.
Other than that, comments can also be used to ignore some code while testing other blocks of code. This offers a simple way to prevent the execution of some lines or write a quick pseudo-code for the program.
Single-Line Comments in Python
In Python, we use the hash symbol
# to write a single-line comment.
Example 1: Writing Single-Line Comments
# printing a string print('Hello world')
Here, the comment is:
# printing a string
This line is ignored by the Python interpreter.
Everything that comes after
# is ignored. So, we can also write the above program in a single line as:
print('Hello world') #printing a string
The output of this program will be the same as in Example 1. The interpreter ignores all the text after
Multi-Line Comments in Python
Python doesn't offer a separate way to write multiline comments. However, there are other ways to get around this issue.
We can use
# at the beginning of each line of comment on multiple lines.
Example 2: Using multiple #
# it is a # multiline # comment
Here, each line is treated as a single comment and all of them are ignored.
String Literals for Multi-line Comments
Even though there is no unique way to write multiline comments in Python, we know that the Python interpreter ignores the string literals that are not assigned to a variable.
So, we can even write a single-line comment as:
#this is a comment 'this is an unassigned string as a comment '
Here, we can see that the second line of the program is a string but is not assigned to any variable or function. So, the interpreter ignores the string.
In a similar way, we can use multiline strings (triple quotes) to write multiline comments.
The quotation character can either be
Example 3: Using String Literals to write Multi-line Comments
''' I am a multiline comment! ''' print("Hello World")
Here, the multiline string isn't assigned to any variable, so it is ignored by the interpreter. Even though it is not technically a multiline comment, it can be used as one.
By convention, the triple quotes that appear right after the function, method or class definition are docstrings (documentation strings).
Docstrings are associated with objects and can be accessed using the
To learn more, visit Python docstrings.
How to Write Better Comments?
- Use comments to describe what a function does and not the specific details on how the function does it.
- Try to remove as many redundant comments as possible. Try writing code that can explain itself, using better function/variable name choice.
- Try to make the comments as short and concise as possible.