Python Indentation

Indentation refers to the spaces at the beginning of a line of code. In Python, indentation is used to define blocks of code and is mandatory.

Unlike many other programming languages, Python uses indentation instead of curly braces {}.

Basic Indentation

Example

if True:
    print("Hello Python")

Output:

Hello Python

Indentation Inside Functions

Example

def greet():
    print("Welcome")
    print("Python")

greet()

Output:

Welcome
Python

Indentation Inside Loops

Example

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

Output:

0
1
2

Missing Indentation Error

Python raises an error if indentation is missing.

Example

if True:
print("Hello")

Output:

IndentationError: expected an indented block

Using Multiple Statements in a Block

Example

age = 18

if age >= 18:
    print("Eligible")
    print("Can Vote")

Output:

Eligible
Can Vote

Nested Indentation

Example

age = 20

if age >= 18:
    print("Adult")

    if age >= 21:
        print("Can Apply")

Output:

Adult

Indentation Using Spaces

Python recommends using 4 spaces for each indentation level.

Example

def show():
    print("Python")

Tabs vs Spaces

You should use either tabs or spaces consistently throughout your code.

Incorrect Example

if True:
	print("Hello")
    print("Python")

Output:

TabError: inconsistent use of tabs and spaces

Summary

• Indentation defines code blocks in Python.
• Indentation is mandatory.
• Python typically uses 4 spaces for indentation.
• Missing indentation causes an IndentationError.
• Consistent indentation improves code readability.
• Avoid mixing tabs and spaces.
• Functions, loops, and conditions all require proper indentation.