/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/*
* NominalToBinary.java
* Copyright (C) 1999 Eibe Frank
*
*/
package weka.filters.unsupervised.attribute;
import weka.filters.*;
import java.io.*;
import java.util.*;
import weka.core.*;
/**
* Converts all nominal attributes into binary numeric attributes. An
* attribute with k values is transformed into k binary attributes
* (using the one-attribute-per-value approach).
* Binary attributes are left binary.
*
* Valid filter-specific options are: <p>
*
* -N <br>
* If binary attributes are to be coded as nominal ones.<p>
*
* @author Eibe Frank (eibe@cs.waikato.ac.nz)
* @version $Revision: 1.1.1.1 $
*/
public class NominalToBinary extends Filter implements UnsupervisedFilter,
OptionHandler {
/** The sorted indices of the attribute values. */
private int[][] m_Indices = null;
/** Are the new attributes going to be nominal or numeric ones? */
private boolean m_Numeric = true;
/**
* Sets the format of the input instances.
*
* @param instanceInfo an Instances object containing the input
* instance structure (any instances contained in the object are
* ignored - only the structure is required).
* @return true if the outputFormat may be collected immediately
* @exception Exception if the input format can't be set
* successfully
*/
public boolean setInputFormat(Instances instanceInfo)
throws Exception {
super.setInputFormat(instanceInfo);
setOutputFormat();
m_Indices = null;
return true;
}
/**
* Input an instance for filtering. Filter requires all
* training instances be read before producing output.
*
* @param instance the input instance
* @return true if the filtered instance may now be
* collected with output().
* @exception IllegalStateException if no input format has been set
*/
public boolean input(Instance instance) {
if (getInputFormat() == null) {
throw new IllegalStateException("No input instance format defined");
}
if (m_NewBatch) {
resetQueue();
m_NewBatch = false;
}
convertInstance(instance);
return true;
}
/**
* Returns an enumeration describing the available options.
*
* @return an enumeration of all the available options.
*/
public Enumeration listOptions() {
Vector newVector = new Vector(1);
newVector.addElement(new Option(
"\tSets if binary attributes are to be coded as nominal ones.",
"N", 0, "-N"));
return newVector.elements();
}
/**
* Parses the options for this object. Valid options are: <p>
*
* -N <br>
* If binary attributes are to be coded as nominal ones.<p>
*
* @param options the list of options as an array of strings
* @exception Exception if an option is not supported
*/
public void setOptions(String[] options) throws Exception {
setBinaryAttributesNominal(Utils.getFlag('N', options));
if (getInputFormat() != null)
setInputFormat(getInputFormat());
}
/**
* Gets the current settings of the filter.
*
* @return an array of strings suitable for passing to setOptions
*/
public String [] getOptions() {
String [] options = new String [1];
int current = 0;
if (getBinaryAttributesNominal()) {
options[current++] = "-N";
}
while (current < options.length) {
options[current++] = "";
}
return options;
}
/**
* Gets if binary attributes are to be treated as nominal ones.
*
* @return true if binary attributes are to be treated as nominal ones
*/
public boolean getBinaryAttributesNominal() {
return !m_Numeric;
}
/**
* Sets if binary attributes are to be treates as nominal ones.
*
* @param bool true if binary attributes are to be treated as nominal ones
*/
public void setBinaryAttributesNominal(boolean bool) {
m_Numeric = !bool;
}
/**
* Set the output format if the class is nominal.
*/
private void setOutputFormat() {
FastVector newAtts;
int newClassIndex;
StringBuffer attributeName;
Instances outputFormat;
FastVector vals;
// Compute new attributes
newClassIndex = getInputFormat().classIndex();
newAtts = new FastVector();
for (int j = 0; j < getInputFormat().numAttributes(); j++) {
Attribute att = getInputFormat().attribute(j);
if (!att.isNominal() || (j == getInputFormat().classIndex())) {
newAtts.addElement(att.copy());
} else {
if (att.numValues() <= 2) {
if (m_Numeric) {
newAtts.addElement(new Attribute(att.name()));
} else {
newAtts.addElement(att.copy());
}
} else {
if (newClassIndex >= 0 && j < getInputFormat().classIndex()) {
newClassIndex += att.numValues() - 1;
}
// Compute values for new attributes
for (int k = 0; k < att.numValues(); k++) {
attributeName =
new StringBuffer(att.name() + "=");
attributeName.append(att.value(k));
if (m_Numeric) {
newAtts.
addElement(new Attribute(attributeName.toString()));
} else {
vals = new FastVector(2);
vals.addElement("f"); vals.addElement("t");
newAtts.
addElement(new Attribute(attributeName.toString(), vals));
}
}
}
}
}
outputFormat = new Instances(getInputFormat().relationName(),
newAtts, 0);
outputFormat.setClassIndex(newClassIndex);
setOutputFormat(outputFormat);
}
/**
* Convert a single instance over if the class is nominal. The converted
* instance is added to the end of the output queue.
*
* @param instance the instance to convert
*/
private void convertInstance(Instance instance) {
double [] vals = new double [outputFormatPeek().numAttributes()];
int attSoFar = 0;
for(int j = 0; j < getInputFormat().numAttributes(); j++) {
Attribute att = getInputFormat().attribute(j);
if (!att.isNominal() || (j == getInputFormat().classIndex())) {
vals[attSoFar] = instance.value(j);
attSoFar++;
} else {
if (att.numValues() <= 2) {
vals[attSoFar] = instance.value(j);
attSoFar++;
} else {
if (instance.isMissing(j)) {
for (int k = 0; k < att.numValues(); k++) {
vals[attSoFar + k] = instance.value(j);
}
} else {
for (int k = 0; k < att.numValues(); k++) {
if (k == (int)instance.value(j)) {
vals[attSoFar + k] = 1;
} else {
vals[attSoFar + k] = 0;
}
}
}
attSoFar += att.numValues();
}
}
}
Instance inst = null;
if (instance instanceof SparseInstance) {
inst = new SparseInstance(instance.weight(), vals);
} else {
inst = new Instance(instance.weight(), vals);
}
copyStringValues(inst, false, instance.dataset(), getInputStringIndex(),
getOutputFormat(), getOutputStringIndex());
inst.setDataset(getOutputFormat());
push(inst);
}
/**
* Main method for testing this class.
*
* @param argv should contain arguments to the filter:
* use -h for help
*/
public static void main(String [] argv) {
try {
if (Utils.getFlag('b', argv)) {
Filter.batchFilterFile(new NominalToBinary(), argv);
} else {
Filter.filterFile(new NominalToBinary(), argv);
}
} catch (Exception ex) {
System.out.println(ex.getMessage());
}
}
}