Mahout: Preference data

Preference data is input to a recommender engine. Usually Preference data contains 3 things.

         1. User id

         2. Item id

         3. Rating (optional in some cases).

One Preference object represents, user’s preference for one item.

org.apache.mahout.cf.taste.model.Preference interface is used to represent a Preference Object. There are two implementations of Preference interface.

a.   GenericPreference

b.   BooleanPreference

a. GenericPreference

GenericPreference instance is constructed using userId, itemId and rating for this item.

Syntax

GenericPreference(long userID, long itemID, float value)

Example

GenericPreference prf = new GenericPreference("1,4,3");

b. BooleanPreference

BooleanPreference instance is constructed using userId, itemId. Rating for an item doesn’t matter here.

Syntax

BooleanPreference(long userID, long itemID)

Example
BooleanPreference pref = new BooleanPreference(1, 5)

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