Control Flow in Python

Control flow is the order in which the program’s code executes. In Python, control flow is regulated by conditional statements, loops, and function calls.

Conditional Statements

Conditional statements allow you to execute different blocks of code based on certain conditions.

The if Statement

The if statement is used to test a condition. If the condition is True, the block of code inside the if statement is executed.

age = 20
if age >= 18:
    print("You are eligible to vote.")

The else Statement

The else statement is used to execute a block of code if the condition in the if statement is False.

age = 15
if age >= 18:
    print("You are eligible to vote.")
else:
    print("You are not eligible to vote yet.")

The elif Statement

The elif (short for else if) statement allows you to check multiple conditions. If the condition for if is False, it checks the condition of the next elif block.

score = 85

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

Indentation in Python

Unlike many other programming languages that use curly braces {} to define blocks of code, Python uses indentation (whitespace at the beginning of a line).

if True:
    print("This is indented")
    print("This is also part of the if block")
print("This is NOT part of the if block")

Shorthand If (Ternary Operator)

If you have only one statement to execute, you can put it on the same line as the if statement. For if-else, Python supports a one-line syntax:

# Syntax: value_if_true if condition else value_if_false
age = 20
status = "Adult" if age >= 18 else "Minor"
print(status)

Logical Operators

You can combine multiple conditions using logical operators: and, or, and not.

x = 10
y = 20

if x > 5 and y > 15:
    print("Both conditions are True")

if x > 15 or y > 15:
    print("At least one condition is True")