我有一个很简单的推荐问题：我想在R中使用recommenderlab构建一个混合推荐器，在这里我推荐MovieLense数据集中已经很喜欢的电影以及热门电影和一些随机电影电影。
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)
)
训练模型后，我想使用userId为给定的用户“预测”电影。 Recommenderlab文档建议，只要用户ID包含在培训数据中，就可以做到这一点。但是，当我尝试在userid中使用newdata进行预测时，收到以下错误消息：
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.
足够公平，我尝试使用向量：
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.
无法真正弄清楚此错误消息的含义。有人知道吗？
答案 0 :(得分：1)
您只需要确定要从培训数据集中向用户推荐项目，如下所示：
> 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)"
否则，预测函数不知道您指的是哪个用户。
您还可以按照以下方式预测测试数据：
> as(predict(recom, test), "list")