Python Functions

A Function is a block of code that performs a specific task. Functions help make code reusable, organized, and easier to maintain.

Creating a Function

Use the def keyword to create a function.

Syntax

def function_name():
    # code

Example

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

greet()

Output:

Welcome to Python

Function with Parameters

Parameters allow you to pass data into a function.

Syntax

def function_name(parameter):
    # code

Example

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

greet("John")

Output:

Hello John

Function with Multiple Parameters

Example

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

add(10, 20)

Output:

30

Return Statement

The return statement sends a value back from a function.

Syntax

def function_name():
    return value

Example

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

result = add(10, 20)

print(result)

Output:

30

Default Parameter Value

You can provide a default value for a parameter.

Example

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

greet()
greet("John")

Output:

Hello Guest
Hello John

Function Returning Multiple Values

Example

def calculate(a, b):
    return a + b, a - b

sum_result, sub_result = calculate(20, 10)

print(sum_result)
print(sub_result)

Output:

30
10

Calling a Function Multiple Times

Example

def welcome():
    print("Welcome")

welcome()
welcome()
welcome()

Output:

Welcome
Welcome
Welcome

Benefits of Functions

• Avoid code repetition.
• Improve code readability.
• Make programs easier to maintain.
• Allow code reuse throughout the application.

Summary

• Functions are created using the def keyword.
• Functions can accept parameters.
• Functions can return values using return.
• Default parameter values can be provided.
• Functions can be called multiple times.
• Functions help organize and reuse code.