Creating Functions With No Input Parameters

00:00 Defining Functions With No Input Parameters. In this course, you’ll use the example of a basic program that creates and maintains a shopping list and prints it out when you’re ready to go to the supermarket.

00:14 Start by creating a shopping list.

00:29 You’re using a dictionary to store the item name as the key and the quantity you need to buy of each item as the value. You can define a function to display the shopping list.

00:54 When you run this script, you’ll get a printout of the shopping list, as seen on-screen.

01:07 The function you’ve defined has no input parameters, as the parentheses in the function signature are empty. The signature is the first line in the function definition.

01:18 You don’t need any input parameters in this example, since the dictionary, shopping_list, is a global variable. This means it can be accessed from everywhere in the program, including from within the function definition. This is called the global scope.

01:34 You can read more about scope in this Real Python tutorial. Using global variables in this way is not a good practice. It can lead to several functions making changes to the same data structure, which can lead to bugs that are hard to find.

01:51 You’ll see how to improve on this later on in this course, when you pass the dictionary to the function as an argument. In the next section, you’ll define a function that requires an input argument.