Python - Indentation

What is Indentation?

In Python, indentation refers to the whitespace at the beginning of a line. Unlike many programming languages that use curly braces {} to define code blocks, Python uses indentation to represent blocks of code.

Why is Indentation Important?

It defines the **structure** and **scope** of code.
Python throws an IndentationError if indentation is not correct.
Makes code more readable and clean.

How to Use Indentation?

Use 4 spaces (recommended by PEP 8) or a tab. Be consistent across your file.

python

 def greet():  print("Hello, World!") # This line is indented by 4 spaces  greet()

When Does Indentation Matter?

In function definitions
In loops (for, while)
In conditionals (if, else, elif)
In classes
Any place where a block of code is expected

Correct vs Incorrect Indentation

Correct

for i in range(3): print("Count:", i)

Incorrect

for i in range(3): print("Count:", i)# IndentationError!

Pros and Cons

Pros

Enforces clean and readable code
No need for curly braces
Structure is visually clear

Cons

Whitespace errors are harder to spot
Mixing tabs and spaces causes bugs
Not beginner-friendly at first

Best Practices

Use 4 spaces per indentation level (PEP 8)
Don’t mix tabs and spaces
Use linters (e.g., Flake8) or IDE support

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