Nested if Statement

In Python, it’s completely valid to place an if, elif, or even else statement inside another if block. This is known as a nested if statement.

This is useful when you want to make a decision inside another decision.

How it Works

First, Python checks the outer condition.
If it’s true, it dives into the inner block.
Inside that block, more conditions are checked.

This lets you create logical branches within existing decisions.

Example:

Let’s categorize a number:

				
					num = 18

if num < 0:
    print("This is a negative number.")
elif num > 0:
    if num <= 10:
        print("Number is between 1 and 10")
    elif num > 10 and num <= 20:
        print("Number is between 11 and 20")
    else:
        print("Number is greater than 20")
else:
    print("This is zero")

Output:

				
					Number is between 11 and 20

Why Use elif?

Nested if blocks help when a decision depends on another. For example, checking if a student passed, then checking their grade category only if they passed.

However, use nested conditions only when needed—too much nesting can make code harder to read.