Functions are reusable chunks of code that accomplish a specified task. Function definition in Python can help you avoid repeated code, organize your application, and improve readability and reusability.
Defining and Calling Functions
In Python, we define a function using the **def** keyword. Here’s a simple function definition:
def greet():
print("Hello, Pythonista!")
This **greet** function prints a string when called. To call a function, you use the function name followed by parentheses:
greet() # prints: Hello, Pythonista!
Arguments and Return Values
Functions can also take arguments (inputs) and return values (outputs). Here’s an example of a function that takes an argument:
def greet(name):
print(f"Hello, {name}!")
We can call this function with a name to greet:
def greet(name):
print(f"Hello, {name}!") prints: Hello, Alice!
Functions can also return values using the **return** keyword. Here’s a function that returns the square of a number:
def square(n):
return n * n
When we call this function with a number, it returns the square of that number:
print(square(5)) # prints: 25
Exercise
Your objective now is to write a function called **‘calculate_area’ **that accepts two inputs, **‘length’ **and ‘width,’ and returns the area of a rectangle calculated as **‘length’ **multiplied by ‘width’.
Conclusion
Understanding functions is essential in Python programming because they allow you to modularize reusable code, enhancing the readability, testing, and organization of your projects. Continue to experiment with different Python functions to get the most out of them!