/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.mahout.cf.taste.example.kddcup;
import org.apache.commons.io.Charsets;
import org.apache.mahout.cf.taste.model.PreferenceArray;
import org.apache.mahout.common.Pair;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileOutputStream;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.util.zip.GZIPOutputStream;
/**
* <p>This class converts a KDD Cup input file into a compressed CSV format. The output format is
* {@code userID,itemID,score,timestamp}. It can optionally restrict its output to exclude
* score and/or timestamp.</p>
*
* <p>Run as: {@code ToCSV (input file) (output file) [num columns to output]}</p>
*/
public final class ToCSV {
private ToCSV() {
}
public static void main(String[] args) throws Exception {
File inputFile = new File(args[0]);
File outputFile = new File(args[1]);
int columnsToOutput = 4;
if (args.length >= 3) {
columnsToOutput = Integer.parseInt(args[2]);
}
OutputStream outStream = new GZIPOutputStream(new FileOutputStream(outputFile));
try (Writer outWriter = new BufferedWriter(new OutputStreamWriter(outStream, Charsets.UTF_8))){
for (Pair<PreferenceArray,long[]> user : new DataFileIterable(inputFile)) {
PreferenceArray prefs = user.getFirst();
long[] timestamps = user.getSecond();
for (int i = 0; i < prefs.length(); i++) {
outWriter.write(String.valueOf(prefs.getUserID(i)));
outWriter.write(',');
outWriter.write(String.valueOf(prefs.getItemID(i)));
if (columnsToOutput > 2) {
outWriter.write(',');
outWriter.write(String.valueOf(prefs.getValue(i)));
}
if (columnsToOutput > 3) {
outWriter.write(',');
outWriter.write(String.valueOf(timestamps[i]));
}
outWriter.write('\n');
}
}
}
}
}