Nested If

Introduction:

Python supports logical conditions from mathematics:
- Equals: a == b
- Not Equals: a != b
- Less than: a < b
- Less than or equal to: a <= b
- Greater than: a > b
- Greater than or equal to: a >= b

Nested If Statements:

You can have if statements inside if statements. This is called nested if statements.

Example:

Here is an example of a nested if statement:

python

x = 41

if x > 10:
    print("Above ten,")
    if x > 20:
        print("and also above 20!")
    else:
        print("but not above 20.")

Output:
```
Above ten,
and also above 20!
```

How It Works:

The outer if statement checks if x is greater than 10. If this condition is true, it prints "Above ten," and then checks the inner if statement.
The inner if statement checks if x is greater than 20. If this condition is true, it prints "and also above 20!". Otherwise, it prints "but not above 20."

Examples:

Simple Nested If Statement:

python

age = 18

if age >= 13:
    print("You are a teenager.")
    if age >= 18:
        print("You are also an adult.")
    else:
        print("But you are not yet an adult.")

Output:

You are a teenager.
You are also an adult.

Nested If with Multiple Conditions:

python

score = 85

if score >= 50:
    print("You passed the exam.")
    if score >= 85:
        print("Excellent job!")
    elif score >= 70:
        print("Good job!")
    else:
        print("You passed, but there is room for improvement.")
else:
    print("You did not pass the exam. Better luck next time.")

Output:
```
You passed the exam.
Excellent job!
```

Exercises:

Nested If Statement:

Write a program to check if a number is positive, and if it is, check if it is even or odd.

python

number = int(input("Enter a number: "))

if number > 0:
    print("The number is positive.")
    if number % 2 == 0:
        print("The number is even.")
    else:
        print("The number is odd.")
else:
    print("The number is not positive.")

Nested If for Age Categories:

Write a program to categorize a person's age group (child, teenager, adult) based on their age.

python

age = int(input("Enter your age: "))

if age < 13:
    print("You are a child.")
elif age >= 13 and age < 20:
    print("You are a teenager.")
    if age == 18 or age == 19:
        print("Almost an adult!")
else:
    print("You are an adult.")

Summary:

Nested if statements allow for more complex decision-making in your programs by enabling multiple levels of conditional checks. Practice using nested if statements to become proficient in handling complex conditional logic in your Python programs