/*
* 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, Hamilton, New Zealand
*
*/
package weka.filters.unsupervised.attribute;
import weka.core.Attribute;
import weka.core.Capabilities;
import weka.core.FastVector;
import weka.core.Instance;
import weka.core.Instances;
import weka.core.Option;
import weka.core.OptionHandler;
import weka.core.RevisionUtils;
import weka.core.SingleIndex;
import weka.core.UnsupportedAttributeTypeException;
import weka.core.Utils;
import weka.core.Capabilities.Capability;
import weka.filters.Filter;
import weka.filters.UnsupervisedFilter;
import java.util.Enumeration;
import java.util.Vector;
/**
<!-- globalinfo-start -->
* 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 first batch of the data.
* <p/>
<!-- globalinfo-end -->
*
<!-- options-start -->
* Valid options are: <p/>
*
* <pre> -C <col>
* Sets the attribute index (default last).</pre>
*
<!-- options-end -->
*
* @author Len Trigg (len@reeltwo.com)
* @version $Revision: 1.9 $
*/
public class StringToNominal
extends Filter
implements UnsupervisedFilter, OptionHandler {
/** for serialization */
static final long serialVersionUID = 8655492378380068939L;
/** The attribute's index setting. */
private SingleIndex m_AttIndex = new SingleIndex("last");
/**
* Returns a string describing this filter
*
* @return a description of the filter suitable for
* displaying in the explorer/experimenter gui
*/
public String globalInfo() {
return "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 first batch of the data.";
}
/**
* Returns the Capabilities of this filter.
*
* @return the capabilities of this object
* @see Capabilities
*/
public Capabilities getCapabilities() {
Capabilities result = super.getCapabilities();
// attributes
result.enableAllAttributes();
result.enable(Capability.MISSING_VALUES);
// class
result.enableAllClasses();
result.enable(Capability.MISSING_CLASS_VALUES);
result.enable(Capability.NO_CLASS);
return result;
}
/**
* 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.
* @throws UnsupportedAttributeTypeException if the selected attribute
* a string attribute.
* @throws Exception if the input format can't be set
* successfully.
*/
public boolean setInputFormat(Instances instanceInfo)
throws Exception {
super.setInputFormat(instanceInfo);
m_AttIndex.setUpper(instanceInfo.numAttributes() - 1);
if (!instanceInfo.attribute(m_AttIndex.getIndex()).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().
* @throws 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.
* @throws 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 a given list of options. <p/>
*
<!-- options-start -->
* Valid options are: <p/>
*
* <pre> -C <col>
* Sets the attribute index (default last).</pre>
*
<!-- options-end -->
*
* @param options the list of options as an array of strings
* @throws Exception if an option is not supported
*/
public void setOptions(String[] options) throws Exception {
String attIndex = Utils.getOption('C', options);
if (attIndex.length() != 0) {
setAttributeIndex(attIndex);
} else {
setAttributeIndex("last");
}
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());
while (current < options.length) {
options[current++] = "";
}
return options;
}
/**
* @return tip text for this property suitable for
* displaying in the explorer/experimenter gui
*/
public String attributeIndexTipText() {
return "Sets which attribute to process. This attribute "
+ "must be a string attribute (\"first\" and \"last\" are valid values)";
}
/**
* Get the index of the attribute used.
*
* @return the index of the attribute
*/
public String getAttributeIndex() {
return m_AttIndex.getSingleIndex();
}
/**
* Sets index of the attribute used.
*
* @param attIndex the index of the attribute
*/
public void setAttributeIndex(String attIndex) {
m_AttIndex.setSingleIndex(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.getIndex()) {
// 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);
}
/**
* Returns the revision string.
*
* @return the revision
*/
public String getRevision() {
return RevisionUtils.extract("$Revision: 1.9 $");
}
/**
* Main method for testing this class.
*
* @param argv should contain arguments to the filter:
* use -h for help
*/
public static void main(String [] argv) {
runFilter(new StringToNominal(), argv);
}
}