3 1 4 Nested If Statements Explained

Key Concepts

Nested if statements in Python allow you to place an if statement inside another if statement. This enables more complex decision-making structures. The key concepts include:

• Basic Structure of Nested If Statements
• Logical Flow
• Practical Applications

1. Basic Structure of Nested If Statements

A nested if statement is an if statement within another if statement. The inner if statement is only evaluated if the outer if statement's condition is true.

Example:

x = 10
y = 5

if x > 5:
    if y > 3:
        print("Both conditions are true")
    

2. Logical Flow

The logical flow of nested if statements involves checking the outer condition first. If it is true, the inner condition is then evaluated. If both conditions are true, the code inside the inner block is executed.

Example:

x = 10
y = 5

if x > 5:
    print("Outer condition is true")
    if y > 3:
        print("Inner condition is true")
    

3. Practical Applications

Nested if statements are useful in scenarios where multiple conditions need to be checked in a specific order. For example, they can be used in grading systems, eligibility checks, or complex decision-making processes.

Example: Grading System

score = 85

if score >= 90:
    print("Grade: A")
else:
    if score >= 80:
        print("Grade: B")
    else:
        if score >= 70:
            print("Grade: C")
        else:
            print("Grade: D")
    

Putting It All Together

By understanding and using nested if statements, you can create more sophisticated decision-making structures in your Python programs. These statements allow you to check multiple conditions in a hierarchical manner, making your code more dynamic and responsive.

Example: Eligibility Check

age = 25
citizenship = "USA"

if age >= 18:
    if citizenship == "USA":
        print("You are eligible to vote")
    else:
        print("You are not a citizen of the USA")
else:
    print("You are not old enough to vote")