Nested if/else means placing one if/else block inside another. The inner condition is only checked when the outer condition is True. This lets you make multi-layered decisions — for example, first checking if someone is old enough, then checking if they have a ticket. Each nesting level adds 4 more spaces of indentation. While powerful, you should limit nesting to 2-3 levels for readability.
Key Points
Nested if = an if statement inside another if statement.
The inner block only runs when the outer condition is True.
Each nesting level adds 4 extra spaces of indentation.
Python uses indentation to determine which block code belongs to.
You can nest else blocks inside if blocks and vice versa.
Keep nesting to 2-3 levels max for readable code.
Consider using elif or and/or operators to reduce nesting.