5 Most Frequently Used R Data Structures For Machine Learning

Notice that when we defined the blood factor for the three patients, we specified an additional vector of four possible blood types using the levels parameter. As a result, even though our data included only types O, AB, and A, all the four types are stored with the blood factor as indicated by the output. Storing the additional level allows for the possibility of adding data with the other blood types in the future. It also ensures that if we were to create a table of blood types, we would know that the B type exists, despite it not being recorded in our data.