Functions in Python

A function is a block of code which only runs when it is called.

You can pass data, known as parameters, into a function.

A function can return data as a result.

Creating a Function

In Python a function is defined using the def keyword:

def my_function():
  print("Hello from a function")    

Calling a Function

To call a function, use the function name followed by parenthesis:

my_function()
Hello from a function

Arguments

Information can be passed into functions as arguments.

Arguments are specified after the function name, inside the parentheses. You can add as many arguments as you want, just separate them with a comma.

def my_function(input_sample):
  print(input_sample + " Office")
my_function("Big")
my_function("Small")

Big Office
Small Office

The terms parameter and argument can be used for the same thing: information that are passed into a function.

Number of Arguments

By default, a function must be called with the correct number of arguments. Meaning that if your function expects 2 arguments, you have to call the function with 2 arguments, not more, and not less.

def my_function(input_1,input_2):
  print(input_1 + " " + input_2)

my_function("Big", "Office")

Big Office

Arbitrary Arguments, *args

If you do not know how many arguments that will be passed into your function, add a * before the parameter name in the function definition.

def my_function(*kids):
  pri