Python Comments and Statements

Python Comments

Python Comments play a crucial role in programming, providing explanations within the code to ensure that its purpose and logic are easily understood by others, or even by yourself after some time has passed. Documenting your code with comments can save you time and effort when you revisit it later.

In Python, comments begin with the hash (#) symbol and extend to the end of the line. They offer a way for programmers to annotate their code, facilitating better comprehension.

Since comments are ignored by the Python interpreter, they do not affect the execution of the program.

Here’s a basic example of a comment in Python:

# This is a comment

As Python comments are not executed, they will not appear in the program’s output. They are meant solely for the reader of the source code.

1. Single-line Comments:

For single-line comments, start the line with a # symbol.

# This is a single-line comment.
# Here is another single-line comment.

2. Inline Comments:

Inline comments are placed on the same line as a code statement. They should begin with a # symbol, followed by a space, and then the comment text. It is recommended to maintain at least two spaces between the code and the inline comment for clarity.

Example demonstrating an inline comment:

n = 10  # increment n by 1
n += 1  # Result is 11

3. Multi-line Comments:

For comments that span multiple lines, you can either prefix each line with a # or use triple quotes (''' or """) for block comments, though the latter is typically used for docstrings.

Using hash symbols:

# This is an extended comment
# that covers several lines
# demonstrating multi-line comments
print('Hello')
Output: Hello

Using triple quotes for multi-line comments:

pythonCopy code
print("Hello Python"
'''Here is an example
of a block comment''')

Output: Hello Python

These methods allow for flexible documentation within Python code, ensuring that it remains accessible and maintainable.

Python Statements

A Python statement is a unit of code that the Python interpreter can execute. For instance, the code a = 5 represents an assignment statement.

Multi-line Statements

By default, Python recognizes the end of a statement with a newline character. However, it’s possible to extend a statement across multiple lines by using the line continuation character (\\).

Normally, statements finish at the end of the line

except under specific conditions, such as when an opening bracket or parenthesis is not yet closed:

 1+3
 +2  # this continuation is not valid

A statement can be explicitly continued onto the next line with a single backslash (\\) at the end of the line:

   1 + \\
   3 + 2 # this continuation is valid

Important: An error occurs if there’s a comment (#) or a space after \\.

Explicit Line Continuation Example:

In Python, line continuation is implicitly handled inside parentheses (), brackets [], and braces {}:

Implicit Line Continuation Example:

(1+3
+2)

6

Here, enclosing the statement in parentheses () allows for implicit line continuation. This principle also applies to brackets [] and braces {}, for example:

['red',
'blue',
    'yellow', '100']

['red', 'blue', 'yellow', '100']

This adjustment maintains the essence and instructional content of the original text while enhancing clarity and incorporating updated examples.