Association rules allow us to explore the relationship between items and sets of items. Such items can be as diverse as the contents of a market basket, the words used in sentences, the components of food products, and so on. Let's go back to the first example: transactions in a shop. Each transaction is composed of one or more items. We are interested in transactions of at least two items because, of course, there cannot be relationships between several items in the purchase of a single item. Imagine customers are purchasing the following sets of items, for which each row represents a transaction. We will use this example more thoroughly in this section:
Cherry coke, chips, lemon
Cherry coke, chicken wings, lemon
Cherry coke, chips, chicken wings, lemon
Chips, chicken wings, lemon
Cherry coke, lemon, chips, chocolate cake
At first sight, you will notice that there seems to be an association between purchases of cherry coke and lemon, as four...