Writing Your First Python Functions - Defining and Calling

Introduction

Functions are a fundamental concept in Python and are used to encapsulate reusable pieces of code. In this guide, we will explore how to define and call your first Python functions.

Defining a Python Function

To define a function in Python, use the def keyword followed by the function name and a pair of parentheses. Here's a simple example:

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

In this example, we defined a function called greet that takes one argument name and prints a greeting message.

Calling a Python Function

To call a Python function, use its name followed by parentheses, passing any required arguments. Here's how you can call the greet function:

greet(`Alice`)
greet(`Bob`)
        

When you call the function with different names, it prints personalized greetings.

Function Parameters and Return Values

Functions can have parameters (inputs) and return values (outputs). Here's an example of a function with parameters and a return value:

def add(x, y):
    result = x + y
    return result
        

In this example, the add function takes two arguments (x and y) and returns their sum. You can call it like this:

result = add(5, 3)
print(`Sum:`, result)
        

The add function returns the result, which is then printed.

Conclusion

Python functions are powerful and allow you to structure your code in a more organized and reusable way. You've now learned how to define and call functions, and you can start creating more complex and modular Python programs.