/// <summary>Read in rating data from a TextReader</summary>
/// <param name="reader">the <see cref="TextReader"/> to read from</param>
/// <param name="user_mapping">mapping object for user IDs</param>
/// <param name="item_mapping">mapping object for item IDs</param>
/// <param name="ignore_first_line">if true, ignore the first line</param>
/// <returns>the rating data</returns>
public static IRatings Read(TextReader reader, IMapping user_mapping = null, IMapping item_mapping = null, bool ignore_first_line = false)
{
if (user_mapping == null)
user_mapping = new IdentityMapping();
if (item_mapping == null)
item_mapping = new IdentityMapping();
if (ignore_first_line)
reader.ReadLine();
var ratings = new Ratings();
string line;
while ( (line = reader.ReadLine()) != null )
{
if (line.Length == 0)
continue;
string[] tokens = line.Split(Constants.SPLIT_CHARS);
if (tokens.Length < 3)
throw new FormatException("Expected at least 3 columns: " + line);
int user_id = user_mapping.ToInternalID(tokens[0]);
int item_id = item_mapping.ToInternalID(tokens[1]);
float rating = float.Parse(tokens[2], CultureInfo.InvariantCulture);
ratings.Add(user_id, item_id, rating);
}
ratings.InitScale();
return ratings;
}
/// <summary>Read in rating data from a TextReader</summary>
/// <param name="reader">the <see cref="TextReader"/> to read from</param>
/// <param name="user_mapping">mapping object for user IDs</param>
/// <param name="item_mapping">mapping object for item IDs</param>
/// <returns>the rating data</returns>
public static ITimedRatings Read(TextReader reader, IEntityMapping user_mapping = null, IEntityMapping item_mapping = null)
{
if (user_mapping == null)
user_mapping = new IdentityMapping();
if (item_mapping == null)
item_mapping = new IdentityMapping();
var ratings = new TimedRatings();
string[] separators = { "::" };
string line;
while ((line = reader.ReadLine()) != null)
{
string[] tokens = line.Split(separators, StringSplitOptions.None);
if (tokens.Length < 4)
throw new FormatException(string.Format("Expected at least 4 columns: {0}", line));
int user_id = user_mapping.ToInternalID(tokens[0]);
int item_id = item_mapping.ToInternalID(tokens[1]);
float rating = float.Parse(tokens[2], CultureInfo.InvariantCulture);
long seconds = uint.Parse(tokens[3]);
var time = new DateTime(seconds * 10000000L).AddYears(1969);
var offset = TimeZone.CurrentTimeZone.GetUtcOffset(time);
time -= offset;
ratings.Add(user_id, item_id, rating, time);
}
return ratings;
}
/// <summary>Read in rating data which will be interpreted as implicit feedback data from a TextReader</summary>
/// <param name="reader">the TextReader to be read from</param>
/// <param name="rating_threshold">the minimum rating value needed to be accepted as positive feedback</param>
/// <param name="user_mapping">user <see cref="IMapping"/> object</param>
/// <param name="item_mapping">item <see cref="IMapping"/> object</param>
/// <param name="ignore_first_line">if true, ignore the first line</param>
/// <returns>a <see cref="IPosOnlyFeedback"/> object with the user-wise collaborative data</returns>
static public IPosOnlyFeedback Read(TextReader reader, float rating_threshold, IMapping user_mapping = null, IMapping item_mapping = null, bool ignore_first_line = false)
{
if (user_mapping == null)
user_mapping = new IdentityMapping();
if (item_mapping == null)
item_mapping = new IdentityMapping();
if (ignore_first_line)
reader.ReadLine();
var feedback = new PosOnlyFeedback<SparseBooleanMatrix>();
string line;
while ((line = reader.ReadLine()) != null)
{
if (line.Trim().Length == 0)
continue;
string[] tokens = line.Split(Constants.SPLIT_CHARS);
if (tokens.Length < 3)
throw new FormatException("Expected at least 3 columns: " + line);
int user_id = user_mapping.ToInternalID(tokens[0]);
int item_id = item_mapping.ToInternalID(tokens[1]);
float rating = float.Parse(tokens[2], CultureInfo.InvariantCulture);
if (rating >= rating_threshold)
feedback.Add(user_id, item_id);
}
return feedback;
}
public void TestCase()
{
string filename = "../../../../tests/example.test";
var mapping = new IdentityMapping();
var ratings = RatingData.Read(filename);
var recommender = new ExternalRatingPredictor() { PredictionFile = filename, UserMapping = mapping, ItemMapping = mapping };
recommender.Train();
for (int i = 0; i < ratings.Count; i++)
Assert.AreEqual(ratings[i], recommender.Predict(ratings.Users[i], ratings.Items[i]));
}
/// <summary>Read in static rating data from a TextReader</summary>
/// <param name="reader">the <see cref="TextReader"/> to read from</param>
/// <param name="size">the number of ratings in the file</param>
/// <param name="user_mapping">mapping object for user IDs</param>
/// <param name="item_mapping">mapping object for item IDs</param>
/// <param name="rating_type">the data type to be used for storing the ratings</param>
/// <param name="test_rating_format">whether there is a rating column in each line or not</param>
/// <param name="ignore_first_line">if true, ignore the first line</param>
/// <returns>the rating data</returns>
static public IRatings Read(
TextReader reader, int size,
IMapping user_mapping = null, IMapping item_mapping = null,
RatingType rating_type = RatingType.FLOAT,
TestRatingFileFormat test_rating_format = TestRatingFileFormat.WITH_RATINGS,
bool ignore_first_line = false)
{
if (user_mapping == null)
user_mapping = new IdentityMapping();
if (item_mapping == null)
item_mapping = new IdentityMapping();
if (ignore_first_line)
reader.ReadLine();
IRatings ratings;
if (rating_type == RatingType.BYTE)
ratings = new StaticByteRatings(size);
else if (rating_type == RatingType.FLOAT)
ratings = new StaticRatings(size);
else
throw new FormatException(string.Format("Unknown rating type: {0}", rating_type));
string line;
while ((line = reader.ReadLine()) != null)
{
if (line.Length == 0)
continue;
string[] tokens = line.Split(Constants.SPLIT_CHARS);
if (test_rating_format == TestRatingFileFormat.WITH_RATINGS && tokens.Length < 3)
throw new FormatException("Expected at least 3 columns: " + line);
if (test_rating_format == TestRatingFileFormat.WITHOUT_RATINGS && tokens.Length < 2)
throw new FormatException("Expected at least 2 columns: " + line);
int user_id = user_mapping.ToInternalID(tokens[0]);
int item_id = item_mapping.ToInternalID(tokens[1]);
float rating = test_rating_format == TestRatingFileFormat.WITH_RATINGS ? float.Parse(tokens[2], CultureInfo.InvariantCulture) : 0;
ratings.Add(user_id, item_id, rating);
}
ratings.InitScale();
return ratings;
}
/// <summary>Read in rating data from a TextReader</summary>
/// <param name="reader">the <see cref="TextReader"/> to read from</param>
/// <param name="user_mapping">mapping object for user IDs</param>
/// <param name="item_mapping">mapping object for item IDs</param>
/// <param name="test_rating_format">whether there is a rating column in each line or not</param>
/// <returns>the rating data</returns>
static public ITimedRatings Read(
TextReader reader,
IMapping user_mapping = null, IMapping item_mapping = null,
TestRatingFileFormat test_rating_format = TestRatingFileFormat.WITH_RATINGS)
{
if (user_mapping == null)
user_mapping = new IdentityMapping();
if (item_mapping == null)
item_mapping = new IdentityMapping();
var ratings = new TimedRatings();
string[] separators = { "::" };
string line;
int seconds_pos = test_rating_format == TestRatingFileFormat.WITH_RATINGS ? 3 : 2;
while ((line = reader.ReadLine()) != null)
{
string[] tokens = line.Split(separators, StringSplitOptions.None);
if (test_rating_format == TestRatingFileFormat.WITH_RATINGS && tokens.Length < 4)
throw new FormatException("Expected at least 4 columns: " + line);
if (test_rating_format == TestRatingFileFormat.WITHOUT_RATINGS && tokens.Length < 3)
throw new FormatException("Expected at least 3 columns: " + line);
int user_id = user_mapping.ToInternalID(tokens[0]);
int item_id = item_mapping.ToInternalID(tokens[1]);
float rating = test_rating_format == TestRatingFileFormat.WITH_RATINGS ? float.Parse(tokens[2], CultureInfo.InvariantCulture) : 0;
long seconds = uint.Parse(tokens[seconds_pos]);
var time = new DateTime(seconds * 10000000L).AddYears(1969);
var offset = TimeZone.CurrentTimeZone.GetUtcOffset(time);
time -= offset;
ratings.Add(user_id, item_id, rating, time);
}
return ratings;
}
/// <summary>Rate a given set of instances and write it to a TextWriter</summary>
/// <param name="recommender">rating predictor</param>
/// <param name="ratings">test cases</param>
/// <param name="writer">the TextWriter to write the predictions to</param>
/// <param name="user_mapping">an <see cref="Mapping"/> object for the user IDs</param>
/// <param name="item_mapping">an <see cref="Mapping"/> object for the item IDs</param>
/// <param name="line_format">a format string specifying the line format; {0} is the user ID, {1} the item ID, {2} the rating</param>
/// <param name="header">if specified, write this string at the start of the output</param>
public static void WritePredictions(
this IRecommender recommender,
IRatings ratings,
TextWriter writer,
IMapping user_mapping = null,
IMapping item_mapping = null,
string line_format = "{0}\t{1}\t{2}",
string header = null)
{
if (user_mapping == null)
user_mapping = new IdentityMapping();
if (item_mapping == null)
item_mapping = new IdentityMapping();
if (header != null)
writer.WriteLine(header);
if (line_format == "ranking")
{
foreach (int user_id in ratings.AllUsers)
if (ratings.ByUser[user_id].Count > 0)
recommender.WritePredictions(
user_id,
new List<int>(from index in ratings.ByUser[user_id] select ratings.Items[index]),
new int[] { },
ratings.ByUser[user_id].Count,
writer,
user_mapping, item_mapping);
}
else
for (int index = 0; index < ratings.Count; index++)
writer.WriteLine(
line_format,
user_mapping.ToOriginalID(ratings.Users[index]),
item_mapping.ToOriginalID(ratings.Items[index]),
recommender.Predict(ratings.Users[index], ratings.Items[index]).ToString(CultureInfo.InvariantCulture));
}
/// <summary>Read in implicit feedback data from a TextReader</summary>
/// <param name="reader">the TextReader to be read from</param>
/// <param name="user_mapping">user <see cref="IMapping"/> object</param>
/// <param name="item_mapping">item <see cref="IMapping"/> object</param>
/// <param name="ignore_first_line">if true, ignore the first line</param>
/// <returns>a <see cref="IPosOnlyFeedback"/> object with the user-wise collaborative data</returns>
public static IPosOnlyFeedback Read(TextReader reader, IMapping user_mapping = null, IMapping item_mapping = null, bool ignore_first_line = false)
{
if (user_mapping == null)
user_mapping = new IdentityMapping();
if (item_mapping == null)
item_mapping = new IdentityMapping();
if (ignore_first_line)
reader.ReadLine();
var feedback = new PosOnlyFeedback<SparseBooleanMatrix>();
string line;
while ((line = reader.ReadLine()) != null)
{
if (line.Trim().Length == 0)
continue;
string[] tokens = line.Split(Constants.SPLIT_CHARS);
if (tokens.Length < 2)
throw new FormatException("Expected at least 2 columns: " + line);
try
{
int user_id = user_mapping.ToInternalID(tokens[0]);
int item_id = item_mapping.ToInternalID(tokens[1]);
feedback.Add(user_id, item_id);
}
catch (Exception)
{
throw new FormatException(string.Format("Could not read line '{0}'", line));
}
}
return feedback;
}
/// <summary>Read in rating data from a TextReader</summary>
/// <param name="reader">the <see cref="TextReader"/> to read from</param>
/// <param name="user_mapping">mapping object for user IDs</param>
/// <param name="item_mapping">mapping object for item IDs</param>
/// <param name="ignore_first_line">if true, ignore the first line</param>
/// <returns>the rating data</returns>
public static ITimedRatings Read(TextReader reader, IEntityMapping user_mapping = null, IEntityMapping item_mapping = null, bool ignore_first_line = false)
{
if (user_mapping == null)
user_mapping = new IdentityMapping();
if (item_mapping == null)
item_mapping = new IdentityMapping();
if (ignore_first_line)
reader.ReadLine();
var ratings = new MyMediaLite.Data.TimedRatings();
var time_split_chars = new char[] { ' ', '-', ':' };
string line;
while ((line = reader.ReadLine()) != null)
{
if (line.Length == 0)
continue;
string[] tokens = line.Split(Constants.SPLIT_CHARS);
if (tokens.Length < 4)
throw new FormatException("Expected at least 4 columns: " + line);
int user_id = user_mapping.ToInternalID(tokens[0]);
int item_id = item_mapping.ToInternalID(tokens[1]);
float rating = float.Parse(tokens[2], CultureInfo.InvariantCulture);
string date_string = tokens[3];
if (tokens[3].StartsWith("\"") && tokens.Length > 4 && tokens[4].EndsWith("\""))
{
date_string = tokens[3] + " " + tokens[4];
date_string = date_string.Substring(1, date_string.Length - 2);
}
uint seconds;
if (date_string.Length == 19) // format "yyyy-mm-dd hh:mm:ss"
{
var date_time_tokens = date_string.Split(time_split_chars);
ratings.Add(
user_id, item_id, rating,
new DateTime(
int.Parse(date_time_tokens[0]),
int.Parse(date_time_tokens[1]),
int.Parse(date_time_tokens[2]),
int.Parse(date_time_tokens[3]),
int.Parse(date_time_tokens[4]),
int.Parse(date_time_tokens[5])));
}
else if (date_string.Length == 10 && date_string[4] == '-') // format "yyyy-mm-dd"
{
var date_time_tokens = date_string.Split(time_split_chars);
ratings.Add(
user_id, item_id, rating,
new DateTime(
int.Parse(date_time_tokens[0]),
int.Parse(date_time_tokens[1]),
int.Parse(date_time_tokens[2])));
}
else if (uint.TryParse(date_string, out seconds)) // unsigned integer value, interpreted as seconds since Unix epoch
{
var time = new DateTime(seconds * 10000000L).AddYears(1969);
var offset = TimeZone.CurrentTimeZone.GetUtcOffset(time);
ratings.Add(user_id, item_id, rating, time - offset);
}
else
ratings.Add(user_id, item_id, rating, DateTime.Parse(date_string, CultureInfo.InvariantCulture));
if (ratings.Count % 200000 == 199999)
Console.Error.Write(".");
if (ratings.Count % 12000000 == 11999999)
Console.Error.WriteLine();
}
ratings.InitScale();
return ratings;
}
/// <summary>Write item predictions (scores) to a TextWriter object</summary>
/// <param name="recommender">the <see cref="IRecommender"/> to use for making the predictions</param>
/// <param name="user_id">ID of the user to make recommendations for</param>
/// <param name="candidate_items">list of candidate items</param>
/// <param name="ignore_items">list of items for which no predictions should be made</param>
/// <param name="num_predictions">the number of items to return per user, -1 if there should be no limit</param>
/// <param name="writer">the <see cref="TextWriter"/> to write to</param>
/// <param name="user_mapping">an <see cref="IEntityMapping"/> object for the user IDs</param>
/// <param name="item_mapping">an <see cref="IEntityMapping"/> object for the item IDs</param>
public static void WritePredictions(
this IRecommender recommender,
int user_id,
System.Collections.Generic.IList<int> candidate_items,
System.Collections.Generic.ICollection<int> ignore_items,
int num_predictions,
TextWriter writer,
IEntityMapping user_mapping, IEntityMapping item_mapping)
{
System.Collections.Generic.IList<Pair<int, float>> ordered_items;
if (user_mapping == null)
user_mapping = new IdentityMapping();
if (item_mapping == null)
item_mapping = new IdentityMapping();
if (num_predictions == -1)
{
var scored_items = new List<Pair<int, float>>();
foreach (int item_id in candidate_items)
if (!ignore_items.Contains(item_id))
{
float score = recommender.Predict(user_id, item_id);
if (score > float.MinValue)
scored_items.Add(new Pair<int, float>(item_id, score));
}
ordered_items = scored_items.OrderByDescending(x => x.Second).ToArray();
}
else {
var comparer = new DelegateComparer<Pair<int, float>>( (a, b) => a.Second.CompareTo(b.Second) );
var heap = new IntervalHeap<Pair<int, float>>(num_predictions, comparer);
float min_relevant_score = float.MinValue;
foreach (int item_id in candidate_items)
if (!ignore_items.Contains(item_id))
{
float score = recommender.Predict(user_id, item_id);
if (score > min_relevant_score)
{
heap.Add(new Pair<int, float>(item_id, score));
if (heap.Count > num_predictions)
{
heap.DeleteMin();
min_relevant_score = heap.FindMin().Second;
}
}
}
ordered_items = new Pair<int, float>[heap.Count];
for (int i = 0; i < ordered_items.Count; i++)
ordered_items[i] = heap.DeleteMax();
}
writer.Write("{0}\t[", user_mapping.ToOriginalID(user_id));
if (ordered_items.Count > 0)
{
writer.Write("{0}:{1}", item_mapping.ToOriginalID(ordered_items[0].First), ordered_items[0].Second.ToString(CultureInfo.InvariantCulture));
for (int i = 1; i < ordered_items.Count; i++)
{
int item_id = ordered_items[i].First;
float score = ordered_items[i].Second;
writer.Write(",{0}:{1}", item_mapping.ToOriginalID(item_id), score.ToString(CultureInfo.InvariantCulture));
}
}
writer.WriteLine("]");
}
/// <summary>Write item predictions (scores) for a given user to a TextWriter object</summary>
/// <param name="recommender">the <see cref="IRecommender"/> to use for making the predictions</param>
/// <param name="user_id">ID of the user to make recommendations for</param>
/// <param name="candidate_items">list of candidate items</param>
/// <param name="ignore_items">list of items for which no predictions should be made</param>
/// <param name="num_predictions">the number of items to return per user, -1 if there should be no limit</param>
/// <param name="writer">the <see cref="TextWriter"/> to write to</param>
/// <param name="user_mapping">an <see cref="IMapping"/> object for the user IDs</param>
/// <param name="item_mapping">an <see cref="IMapping"/> object for the item IDs</param>
public static void WritePredictions(
this IRecommender recommender,
int user_id,
ICollection<int> candidate_items,
ICollection<int> ignore_items,
int num_predictions,
TextWriter writer,
IMapping user_mapping, IMapping item_mapping)
{
if (user_mapping == null)
user_mapping = new IdentityMapping();
if (item_mapping == null)
item_mapping = new IdentityMapping();
var ordered_items = recommender.Recommend(
user_id, n:num_predictions,
ignore_items:ignore_items, candidate_items:candidate_items);
writer.Write("{0}\t[", user_mapping.ToOriginalID(user_id));
if (ordered_items.Count > 0)
{
writer.Write("{0}:{1}", item_mapping.ToOriginalID(ordered_items[0].Item1), ordered_items[0].Item2.ToString(CultureInfo.InvariantCulture));
for (int i = 1; i < ordered_items.Count; i++)
{
int item_id = ordered_items[i].Item1;
float score = ordered_items[i].Item2;
writer.Write(",{0}:{1}", item_mapping.ToOriginalID(item_id), score.ToString(CultureInfo.InvariantCulture));
}
}
writer.WriteLine("]");
}
