/*
* 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.
*/
/*
* StringToNominal.java
* Copyright (C) 2002 University of Waikato
*
*/
package weka.filters.unsupervised.attribute;
import weka.filters.*;
import java.util.Enumeration;
import java.util.Vector;
import weka.core.Attribute;
import weka.core.FastVector;
import weka.core.Instance;
import weka.core.Instances;
import weka.core.Option;
import weka.core.OptionHandler;
import weka.core.Utils;
import weka.core.UnsupportedAttributeTypeException;
/**
* Converts a string attribute (i.e. unspecified number of values) to nominal
* (i.e. set number of values). You should ensure that all string values that
* will appear are represented in the dataset.<p>
*
* Valid filter-specific options are: <p>
*
* -C col <br>
* Index of the attribute to be changed. (default last)<p>
*
* @author Len Trigg (len@reeltwo.com)
* @version $Revision: 1.1.1.1 $
*/
public class StringToNominal extends Filter
implements UnsupervisedFilter, OptionHandler {
/** The attribute index setting (allows -1 = last). */
private int m_AttIndexSet = -1;
/** The attribute index. */
private int m_AttIndex;
/**
* 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 UnsupportedAttributeTypeException if the selected attribute
* a string attribute.
* @exception Exception if the input format can't be set
* successfully.
*/
public boolean setInputFormat(Instances instanceInfo)
throws Exception {
super.setInputFormat(instanceInfo);
m_AttIndex = m_AttIndexSet;
if (m_AttIndex < 0) {
m_AttIndex = instanceInfo.numAttributes() - 1;
}
if (!instanceInfo.attribute(m_AttIndex).isString()) {
throw new UnsupportedAttributeTypeException("Chosen attribute is not of type string.");
}
return false;
}
/**
* Input an instance for filtering. The instance is processed
* and made available for output immediately.
*
* @param instance the input instance.
* @return true if the filtered instance may now be
* collected with output().
* @exception IllegalStateException if no input structure has been defined.
*/
public boolean input(Instance instance) {
if (getInputFormat() == null) {
throw new IllegalStateException("No input instance format defined");
}
if (m_NewBatch) {
resetQueue();
m_NewBatch = false;
}
if (isOutputFormatDefined()) {
Instance newInstance = (Instance)instance.copy();
push(newInstance);
return true;
}
bufferInput(instance);
return false;
}
/**
* Signifies that this batch of input to the filter is finished. If the
* filter requires all instances prior to filtering, output() may now
* be called to retrieve the filtered instances.
*
* @return true if there are instances pending output.
* @exception IllegalStateException if no input structure has been defined.
*/
public boolean batchFinished() {
if (getInputFormat() == null) {
throw new IllegalStateException("No input instance format defined");
}
if (!isOutputFormatDefined()) {
setOutputFormat();
// Convert pending input instances
for(int i = 0; i < getInputFormat().numInstances(); i++) {
push((Instance) getInputFormat().instance(i).copy());
}
}
flushInput();
m_NewBatch = true;
return (numPendingOutput() != 0);
}
/**
* 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 the attribute index (default last).",
"C", 1, "-C <col>"));
return newVector.elements();
}
/**
* Parses the options for this object. Valid options are: <p>
*
* -C col <br>
* The column containing the values to be merged. (default last)<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 {
String attributeIndex = Utils.getOption('C', options);
if (attributeIndex.length() != 0) {
if (attributeIndex.toLowerCase().equals("last")) {
setAttributeIndex(-1);
} else if (attributeIndex.toLowerCase().equals("first")) {
setAttributeIndex(0);
} else {
setAttributeIndex(Integer.parseInt(attributeIndex) - 1);
}
} else {
setAttributeIndex(-1);
}
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 [6];
int current = 0;
options[current++] = "-C";
options[current++] = "" + (getAttributeIndex() + 1);
while (current < options.length) {
options[current++] = "";
}
return options;
}
/**
* Get the index of the attribute used.
*
* @return the index of the attribute
*/
public int getAttributeIndex() {
return m_AttIndexSet;
}
/**
* Sets index of the attribute used.
*
* @param index the index of the attribute
*/
public void setAttributeIndex(int attIndex) {
m_AttIndexSet = attIndex;
}
/**
* Set the output format. Takes the current average class values
* and m_InputFormat and calls setOutputFormat(Instances)
* appropriately.
*/
private void setOutputFormat() {
Instances newData;
FastVector newAtts, newVals;
// Compute new attributes
newAtts = new FastVector(getInputFormat().numAttributes());
for (int j = 0; j < getInputFormat().numAttributes(); j++) {
Attribute att = getInputFormat().attribute(j);
if (j != m_AttIndex) {
// We don't have to copy the attribute because the
// attribute index remains unchanged.
newAtts.addElement(att);
} else {
// Compute list of attribute values
newVals = new FastVector(att.numValues());
for (int i = 0; i < att.numValues(); i++) {
newVals.addElement(att.value(i));
}
newAtts.addElement(new Attribute(att.name(), newVals));
}
}
// Construct new header
newData = new Instances(getInputFormat().relationName(), newAtts, 0);
newData.setClassIndex(getInputFormat().classIndex());
setOutputFormat(newData);
}
/**
* 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 StringToNominal(), argv);
} else {
Filter.filterFile(new StringToNominal(), argv);
}
} catch (Exception ex) {
System.out.println(ex.getMessage());
}
}
}