recommenderlab (version 0.1-9)

realRatingMatrix: Class "realRatingMatrix": Real-valued Rating Matrix

Description

A matrix containing ratings (typically 1-5 stars, etc.).

Objects from the Class

Objects can be created by calls of the form new("realRatingMatrix", data = m), where m is sparse matrix of class dgCMatrix in package Matrix or by coercion from a regular matrix, a data.frame containing user/item/rating triplets as rows, or a sparse matrix in triplet form (dgTMatrix in package Matrix).

Extends

Class "ratingMatrix", directly.

See Also

See ratingMatrix inherited methods, binaryRatingMatrix, topNList, getList and getData.frame. Also see dgCMatrix, dgTMatrix and ngCMatrix in Matrix.

Examples

## create a matrix with ratings
m <- matrix(sample(c(NA,0:5),100, replace=TRUE, prob=c(.7,rep(.3/6,6))),
	nrow=10, ncol=10, dimnames = list(
	    user=paste('u', 1:10, sep=''),
	    item=paste('i', 1:10, sep='')
    ))
m

## coerce into a realRatingMAtrix
r <- as(m, "realRatingMatrix")
r

## get some information
dimnames(r)
rowCounts(r)
colCounts(r)
rowMeans(r)


## histogram of ratings
hist(getRatings(r), breaks="FD")

## inspect a subset
image(r[1:5,1:5])

## coerce it back to see if it worked
as(r, "matrix")

## coerce to data.frame (user/item/rating triplets)
as(r, "data.frame")

## binarize into a binaryRatingMatrix with all 4+ rating a 1
b <- binarize(r, minRating=4)
b
as(b, "matrix")