In this section, we will explore the MovieLense
dataset. For this purpose, we will use recommenderlab
to build recommender systems and ggplot2
to visualize their results. Let's load the packages and the data:
library("recommenderlab") library("ggplot2") data(MovieLense) class(MovieLense) ## [1] "realRatingMatrix" ## attr(,"package") ## [1] "recommenderlab"
MovieLense
is a realRatingMatrix
object containing a dataset about movie ratings. Each row corresponds to a user, each column to a movie, and each value to a rating.
Let's take a quick look at MovieLense
. As explained in the previous section, there are some generic methods that can be applied to realRatingMatrix
objects. We can extract their size using dim
:
dim(MovieLense) ## [1] 943 1664
There are 943
users and 1664
movies. Since realRatingMatrix
is an S4 class, the components of the objects are contained in MovieLense
slots. We can see all the slots using slotNames
, which displays all the...