Time for action – defining functions

Let's define the following simple function:

1. Print Hello and a given name in the following way:

   >>> def print_hello(name):
   ...     print('Hello ' + name)
   ...
   

   Call the function as follows:

   >>> print_hello('Ivan')
   Hello Ivan
   

2. Some functions do not have arguments, or the arguments have default values. Give the function a default argument value as follows:

   >>> def print_hello(name='Ivan'):
   ...     print('Hello ' + name)
   ...
   >>> print_hello()
   Hello Ivan
   

3. Usually, we want to return a value. Define a function, which doubles input values as follows:

   >>> def double(number):
   ...     return 2 * number
   ...
   >>> double(3)
   6
   

What just happened?

We learned how to define functions. Functions can have default argument values and return values.