Prev Next

Python Functions

A function is a block of organized, reusable code that performs a single action. Functions provide better modularity and reusability in your programs.

Example 1: Defining and Calling a Simple Function

Define a function that greets a person.

# Defining and calling a function
def greet(name):
    print(f"Hello, {name}!")

greet("Karthick AG")
greet("Rohini")

Hello, Karthick AG!

Hello, Rohini!

Example 2: Function with Return Value

Calculate the area of a circle given the radius.

# Function with return value
import math
def circle_area(radius):
    return math.pi * radius ** 2

area = circle_area(5)
print("Area of circle:", area)

Area of circle: 78.53981633974483

Example 3: Function with Default Parameters

Display information about a person, with default age and city.

# Function with default parameters
def display_info(name, age=30, city="Trichy"):
    print(f"Name: {name}, Age: {age}, City: {city}")

display_info("Akila")
display_info("Dhanalakshmi", age=28)

Name: Akila, Age: 30, City: Trichy

Name: Dhanalakshmi, Age: 28, City: Trichy

Example 4: Function with Variable-Length Arguments

Calculate the sum of multiple numbers.

# Function with variable-length arguments
def calculate_sum(*numbers):
    total = sum(numbers)
    print("Sum:", total)

calculate_sum(10, 20)
calculate_sum(5, 10, 15, 20)

Sum: 30

Sum: 50

Example 5: Recursive Function

Calculate the factorial of a number using recursion.

# Recursive function for factorial
def factorial(n):
    if n == 1:
        return 1
    else:
        return n * factorial(n - 1)

result = factorial(5)
print("Factorial of 5:", result)

Factorial of 5: 120

Explanation: Functions allow code reuse and better organization. They can accept parameters, return values, and even call themselves recursively.

Prev Next