/**
* 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.df.data;
import java.util.StringTokenizer;
import org.apache.commons.lang.ArrayUtils;
import org.apache.mahout.matrix.DenseVector;
/**
* Converts String to Instance using a Dataset
*/
public class DataConverter {
private final Dataset dataset;
public DataConverter(Dataset dataset) {
this.dataset = dataset;
}
public Instance convert(int id, String string) {
// all attributes (categorical, numerical), ignored, label
int nball = dataset.nbAttributes() + dataset.getIgnored().length + 1;
StringTokenizer tokenizer = new StringTokenizer(string, ", ");
if (tokenizer.countTokens() != nball) {
throw new IllegalArgumentException("Wrong number of attributes in the string");
}
int nbattrs = dataset.nbAttributes();
DenseVector vector = new DenseVector(nbattrs);
int aId = 0;
int label = -1;
for (int attr = 0; attr < nball; attr++) {
String token = tokenizer.nextToken();
if (ArrayUtils.contains(dataset.getIgnored(), attr)) {
continue; // IGNORED
}
if (attr == dataset.getLabelId()) {
label = dataset.labelCode(token);
} else if (dataset.isNumerical(aId)) {
vector.set(aId++, Double.parseDouble(token));
} else {
vector.set(aId, dataset.valueOf(aId, token));
aId++;
}
}
if (label == -1)
throw new IllegalStateException("Label not found!");
return new Instance(id, vector, label);
}
}