The if Statement

• Used to test a condition.
• If the condition is True, the indented block of code executes.
• If the condition is False, the block is skipped.

Syntax:

if condition:
    # Code executes if condition is True

Example:

age = 20
if age >= 18:
    print("You are an adult.")

Important Note:

• Indentation is crucial in Python.
• Statements with the same indentation belong to the same block.
• Different indentation levels define separate blocks.

The if-else Statement

• Adds an alternative block when the condition is False.

Syntax:

if condition:
    # Code executes if condition is True
else:
    # Code executes if condition is False

Example:

age = 16
if age >= 18:
    print("You are an adult.")
else:
    print("You are a minor.")

The elif Statement

• Used when there are multiple conditions.
• Executes the first True condition and skips the rest.

Syntax:

if condition1:
    # Code executes if condition1 is True
elif condition2:
    # Code executes if condition1 is False and condition2 is True
else:
    # Code executes if all conditions are False

Example:

age = 14
if age < 13:
    print("Child")
elif age < 18:
    print("Teenager")
else:
    print("Adult")

Boolean Expressions and Conditional Execution

Boolean Expressions:

• A Boolean expression evaluates to True or False.
• Used in if, if-else, and elif statements.

Relational Operators:

OperatorMeaning>Greater than<Less than>=Greater than or equal to<=Less than or equal to==Equal to!=Not equal to

Logical Operators:

OperatorMeaningandBoth conditions must be TrueorAt least one condition must be TruenotNegates a condition

Example with Boolean Expressions:

x = 10
y = 5

if x > y and y > 0:
    print("Both conditions are True")