I have a recommendation problem that is fairly simple: I would like build a hybrid recommender with recommenderlab in R where I recommend already liked movies in the MovieLense data set together with popular movies and some random movies.
library(recommenderlab)
data("MovieLense")
MovieLense100 <- MovieLense[rowCounts(MovieLense) > 100,]
train <- MovieLense100[1:100]
test <- MovieLense100[101:103]
## mix popular movies with a random recommendations for diversity and
## rerecommend some movies the user liked.
recom <- HybridRecommender(
Recommender(train, method = "POPULAR"),
Recommender(train, method = "RANDOM"),
Recommender(train, method = "RERECOMMEND"),
weights = c(.6, .1, .3)
)
When I have trained the model I would like to "predict" the movies for a given user using the userId. The Recommenderlab documentation suggests that this is possible as long as the userid is in the training data. However, when I try predicting using a userid in newdata I get the following error message:
as(predict(object = recom, newdata = 1), "list")
#> Error in object@predict(object@model, newdata, n = n, data = data, type = type, : If newdata is a user id then data needes to be the training dataset.
Fair enough, I try with a vector:
as(predict(recom, newdata = c(1,5)), "list")
#> Error in object@predict(object@model, newdata, n = n, data = data, type = type, : If newdata is a user id then data needes to be the training dataset.
Can't really figure out what this error message mean. Does anybody know?
You just need to precise that you are recommending items to the user or users from the training dataset as followed :
> as(predict(recom, 1, data = train), "list")
$`1`
[1] "Hearts and Minds (1996)" "Boys, Les (1997)" "Great Day in Harlem, A (1994)"
[4] "Dangerous Beauty (1998)" "Tough and Deadly (1995)" "Two or Three Things I Know About Her (1966)"
[7] "Santa with Muscles (1996)" "Margaret's Museum (1995)" "Brassed Off (1996)"
[10] "Thousand Acres, A (1997)"
> as(predict(recom, 1:10, data = train), "list")
$`1`
[1] "Dangerous Beauty (1998)" "Great Day in Harlem, A (1994)" "Hearts and Minds (1996)"
[4] "Boys, Les (1997)" "Santa with Muscles (1996)" "Two or Three Things I Know About Her (1966)"
[7] "Tough and Deadly (1995)" "Saint of Fort Washington, The (1993)" "Whole Wide World, The (1996)"
[10] "Margaret's Museum (1995)"
$`5`
[1] "Boys, Les (1997)" "Two or Three Things I Know About Her (1966)" "Santa with Muscles (1996)"
[4] "Dangerous Beauty (1998)" "Great Day in Harlem, A (1994)" "Whole Wide World, The (1996)"
[7] "Hearts and Minds (1996)" "Brassed Off (1996)" "Saint of Fort Washington, The (1993)"
[10] "Celestial Clockwork (1994)"
$`6`
[1] "Dangerous Beauty (1998)" "Two or Three Things I Know About Her (1966)" "Santa with Muscles (1996)"
[4] "Tough and Deadly (1995)" "Brassed Off (1996)" "Crooklyn (1994)"
[7] "Great Day in Harlem, A (1994)" "Hearts and Minds (1996)" "Saint of Fort Washington, The (1993)"
[10] "Boys, Les (1997)"
$`7`
[1] "Two or Three Things I Know About Her (1966)" "Tough and Deadly (1995)" "Santa with Muscles (1996)"
[4] "Dangerous Beauty (1998)" "Hearts and Minds (1996)" "Great Day in Harlem, A (1994)"
[7] "Boys, Les (1997)" "Brassed Off (1996)" "Margaret's Museum (1995)"
[10] "Crooklyn (1994)"
$`10`
[1] "Dangerous Beauty (1998)" "Great Day in Harlem, A (1994)" "Hearts and Minds (1996)"
[4] "Tough and Deadly (1995)" "Two or Three Things I Know About Her (1966)" "Boys, Les (1997)"
[7] "Santa with Muscles (1996)" "Brassed Off (1996)" "Margaret's Museum (1995)"
[10] "Crooklyn (1994)"
$`11`
[1] "Two or Three Things I Know About Her (1966)" "Hearts and Minds (1996)" "Great Day in Harlem, A (1994)"
[4] "Tough and Deadly (1995)" "Brassed Off (1996)" "Dangerous Beauty (1998)"
[7] "Boys, Les (1997)" "Santa with Muscles (1996)" "Thousand Acres, A (1997)"
[10] "Horse Whisperer, The (1998)"
$`13`
[1] "Santa with Muscles (1996)" "Brassed Off (1996)" "Tough and Deadly (1995)" "Boys, Les (1997)"
[5] "Thousand Acres, A (1997)" "Margaret's Museum (1995)" "Total Eclipse (1995)" "Love! Valour! Compassion! (1997)"
[9] "Withnail and I (1987)" "Prefontaine (1997)"
$`15`
[1] "Two or Three Things I Know About Her (1966)" "Boys, Les (1997)" "Great Day in Harlem, A (1994)"
[4] "Tough and Deadly (1995)" "Dangerous Beauty (1998)" "Saint of Fort Washington, The (1993)"
[7] "Santa with Muscles (1996)" "Hearts and Minds (1996)" "Celestial Clockwork (1994)"
[10] "Whole Wide World, The (1996)"
$`16`
[1] "Great Day in Harlem, A (1994)" "Dangerous Beauty (1998)" "Hearts and Minds (1996)"
[4] "Two or Three Things I Know About Her (1966)" "Boys, Les (1997)" "Santa with Muscles (1996)"
[7] "Tough and Deadly (1995)" "Brassed Off (1996)" "Crooklyn (1994)"
[10] "Thousand Acres, A (1997)"
$`18`
[1] "Great Day in Harlem, A (1994)" "Two or Three Things I Know About Her (1966)" "Dangerous Beauty (1998)"
[4] "Hearts and Minds (1996)" "Santa with Muscles (1996)" "Tough and Deadly (1995)"
[7] "Boys, Les (1997)" "Whole Wide World, The (1996)" "Margaret's Museum (1995)"
[10] "Saint of Fort Washington, The (1993)"
Otherwise, the predict function we not know what user are you referring to.
You can also predict on test data as followed :
> as(predict(recom, test), "list")