For more information on concepts covered in this lesson, you can check out Python Scope & the LEGB Rule: Resolving Names in Your Code.
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.
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.
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