Statement, Indentation and Comment in Python

Here, we will discuss Statements in Python, Indentation in Python, and Comments in Python. We will also discuss different rules and examples for Python Statement, Python Indentation, Python Comment, and the Difference Between 'Docstrings' and 'Multi-line Comments.

1. Statement in Python

A Python statement is an instruction that the Python interpreter can execute. There are different types of statements in Python language as Assignment statements, Conditional statements, Looping statements, etc.

Example:

x = 10         # Assignment statement
y = 20
print(x + y)   # Function call statement

30

Each line above is a statement.

There are several types of statements in Python, most of them are listed below:

1. Assignment Statements: store values in variables.

name = "Python"
age = 30

2. Conditional Statements: make decisions in code.

if age > 18:
    print("You are an adult")
else:
    print("You are a minor")

3. Looping Statements: repeat tasks.

for i in range(3):
    print("Hello")

4. Import Statements: include external modules.

import math
print(math.sqrt(16))

5. Exception Handling Statements: handle errors safely.

try:
    x = 1 / 0
except ZeroDivisionError:
    print("Division by zero not allowed")

6. Flow Control Statements: break, continue, pass, and return.

7. Multi-line Statements

Some statements are too long to fit on one line. Python allows breaking them into multiple lines:

7.1 Using backslash (\)

s = 1 + 2 + 3 + \
    4 + 5 + 6 + \
    7 + 8 + 9
print(s)

7.2 Using parentheses ()

n = (1 * 2 * 3 +
     4 + 5 + 6)
print(n)

7.3 Using square brackets []

footballers = [
    "Messi",
    "Neymar",
    "Suarez"
]
print(footballers)

7.4 Using braces {}

numbers = {1, 2, 3,
           4, 5}
print(numbers)

2. Indentation in Python

In Python, indentation (spaces or tabs at the beginning of a line) is used to define blocks of code. This is different from most programming languages that use curly braces { } for grouping code.

Example:

site = "gfg"

if site == "gfg":
    print("Logging on to GeeksforGeeks...")
else:
    print("Wrong site")

print("All set!")

Logging on to GeeksforGeeks...
All set!

Rules of Indentation in Python

• All statements inside a block must have the same indentation level.
• Standard indentation in Python is 4 spaces (PEP 8 style guide).
• Mixing tabs and spaces in indentation is not allowed.
• Improper indentation will cause an IndentationError.

Example: Indentation in Loops

j = 1
while j <= 5:
    print(j)     # inside loop
    j = j + 1

print("Done")    # outside loop

1
2
3
4
5
Done

If we forget to indent properly, Python will throw an error.

3. Comments in Python

Comments are text in the code meant for humans, not the Python interpreter. They are ignored during execution.

They are useful for:

• Explaining complex logic
• Adding notes for future reference
• Making code easier for others to understand

3.1 Single-line Comments

Start with # and continue until the end of the line.

# This is a single-line comment
a, b = 5, 10
sum = a + b  # adding two numbers
print(sum)

15

3.2 Multi-line Comments

Python doesn’t have official multi-line comments, but you can use:

Multiple # lines

# This is line 1
# This is line 2
# This is line 3
print("Hello Python")

Triple quotes (""" or ''')

"""
This is a multi-line comment
that spans across multiple lines
"""
print("GeeksforGeeks")

4. Docstrings in Python

Docstrings are documentation strings that look like multi-line comments but serve a special purpose: they explain how functions, classes, or modules work.

Example:

def greet():
    """This function prints a greeting message"""
    print("Hello, World!")

greet()

print(greet.__doc__)  # Access the docstring

Hello, World!
This function prints a greeting message

Difference Between Docstrings and Multi-line Comments

Related Articles:

• Python Operators
• Python Functions
• Python Data Types