Python

What Are Functions in Python? See Examples

Functions in Python are blocks of reusable code that perform a specific task. Instead of writing the same code repeatedly, you can define a function once and use it multiple times.

Functions improve code readability, reusability, and maintainability.

Why Functions Are Important

Functions help to:

Reduce code duplication
Organize programs into logical blocks
Make debugging easier
Improve scalability

Example:

def greet():
    print("Hello, Python!")

How to Define a Function in Python

A function is defined using the def keyword.

def greet():
    print("Welcome to Python")

Calling a Function

To execute a function, simply call it by its name.

greet()

Function Parameters and Arguments

Parameters allow passing data to functions.

def greet(name):
    print("Hello", name)

greet("Sagar")

Return Statement

Functions can return values using the return keyword.

def add(a, b):
    return a + b

result = add(5, 3)

Default Parameters

You can assign default values to parameters.

def greet(name="User"):
    print("Hello", name)

Keyword Arguments

Arguments can be passed using parameter names.

greet(name="Aman")

Variable Scope in Functions

Local variables: Defined inside a function
Global variables: Defined outside a function

x = 10

def show():
    x = 5
    print(x)

Best Practices for Functions

✔ Use meaningful function names
✔ Keep functions small
✔ Use comments when needed
✔ Avoid too many parameters

Conclusion

Functions are a core building block in Python programming. They help write clean, reusable, and efficient code, making programs easier to understand and maintain.