Named Functions

But Python also lets us to create (and name) our own functions.

• Key term: named function(s)

We can define or name a function using the def keyword. A function definition includes a few core components:

• The name of the new function

• The list of function arguments

• The sequence of statements to execute when the function is called

The core syntax for defining your own function:

# use def keyword to define function name
def function_name(argument):
 statement(s)
 return result

Let’s unpack each of those components.

• def function_name() is the name you are giving to the function you create- this is the header for the function definition.

  • Function names have many of the same rules as variable names- no spaces or special characters.

• argument is the argument that will be passed to the function.

  • When we are initially defining the function, the argument value is typically a placeholder.

  • Later in the program when we call the named function, the argument being passed to the function goes in these parenthesis.

• The nested or indented line statement(s) is the body of the function definition. It includes a sequence of statements to execute when the function is called.

• The nested or indented line return result is a placeholder for the function output or endpoint- it is also part of the body of the function definition.