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

In Python a function is defined using the def keyword:

  def my_function():
    return "Hello from a python function"

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

  def my_function():
    print("Function called")
  my_function()

Information can be passed into functions as arguments. Arguments are specified after the function name inside the parenthesis. You can add as many arguments as you want, just separate them with a comma.

  def sum(num1, num2):
    print(num1+num2)

  sum(5, 10)
  sum(20, 60)
  sum(100, 231)