// Написать getTopNRecommendations
public static List <PredictedItemRating> getTopNRecommendations(List <PredictedItemRating> recommendations, int topN)
{
PredictedItemRating.sort(recommendations);
List <PredictedItemRating> topRecommendations = new List <PredictedItemRating>();
recommendations.ForEach(delegate(PredictedItemRating r)
{
if (topRecommendations.Count >= topN)
{
return;
}
topRecommendations.Add(r);
});
return(topRecommendations);
}
public List <PredictedItemRating> recommend(BookUser user, int topN)
{
List <PredictedItemRating> recommendations = new List <PredictedItemRating>();
double maxRating = -1.0d;
for (int i = 0; i < dataSet.getBooks().Count; i++)
{
if (!skipItem(user, dataSet.getBooks()[i]))
{
double predictedRating = predictRating(user, dataSet.getBooks()[i]);
if (maxRating < predictedRating)
{
maxRating = predictedRating;
}
if (!Double.IsNaN(predictedRating))
{
recommendations.Add(new PredictedItemRating(user.UserId, dataSet.getBooks()[i].getId(), predictedRating));
}
}
else
{
if (verbose)
{
Console.WriteLine("Skipping item: " + dataSet.getBooks()[i].getName());
}
}
}
this.maxPredictedRating.Add(user.UserId, maxRating);
List <PredictedItemRating> topNRecommendations = PredictedItemRating.getTopNRecommendations(recommendations, topN);
if (verbose)
{
PredictedItemRating.printUserRecommendations(user, dataSet, topNRecommendations);
}
return(topNRecommendations);
}
