Python Functions Overview

What is a Function?

A function is a block of reusable code that performs a specific task. Functions help in code reusability, organization, and readability.

Types of Functions

  • Built-in Functions: Predefined functions like print(), len(), and sum().
  • User-defined Functions: Functions created by programmers to perform specific tasks.

Defining a Function

Functions in Python are defined using the def keyword.

Example: Creating a Simple Function

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

greet()

Try It Now

Function Parameters and Arguments

Functions can accept parameters to pass values.

Example: Function with Parameters

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

greet("Alice")

Try It Now

Return Statement

Functions can return values using the return keyword.

Example: Function with Return Value

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

result = add(3, 5)
print(result)

Try It Now

Default Parameter Values

If a function parameter has a default value, it can be omitted when calling the function.

Example: Function with Default Parameters

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

greet()
greet("Alice")

Try It Now

Key Takeaways

  • Functions make code reusable and modular.
  • Functions can have parameters and return values.
  • Default parameters allow flexibility in function calls.