我在过去一个月左右的时间里一直在自己学习WEKA API(我是学生)。我正在做的是编写一个程序,该程序将过滤一组特定的数据并最终为其构建贝叶网络,而一周前,我已经完成了离散化类和属性选择类。就在几天前伊朗方法,完成此操作后,我开始在属性选择类中遇到此错误:
Exception in thread "main" weka.core.WekaException:
weka.attributeSelection.CfsSubsetEval: Not enough training instances with class labels (required: 1, provided: 0)!
at weka.core.Capabilities.test(Capabilities.java:1138)
at weka.core.Capabilities.test(Capabilities.java:1023)
at weka.core.Capabilities.testWithFail(Capabilities.java:1302)
at weka.attributeSelection.CfsSubsetEval.buildEvaluator(CfsSubsetEval.java:331)
at weka.attributeSelection.AttributeSelection.SelectAttributes(AttributeSelection.java:597)
at weka.filters.supervised.attribute.AttributeSelection.batchFinished(AttributeSelection.java:456)
at weka.filters.Filter.useFilter(Filter.java:663)
at AttributeSelectionFilter.selectionFilter(AttributeSelectionFilter.java:29)
at Runner.main(Runner.java:70)
在更改工作之前,我的属性选择还不错,所以我认为我在离散班级中可能做错了什么。这个问题的另一部分与此有关,因为我还注意到我的离散化类似乎并没有真正使数据离散。它只是将所有数字数据放在一个范围内,而不是像Fayyad&那样战略性地汇总它。伊朗应该。
这是我的离散类:
import weka.core.Instances;
import weka.filters.Filter;
import weka.filters.supervised.attribute.Discretize;
import weka.filters.unsupervised.attribute.NumericToNominal;
public class DiscretizeFilter
{
private Instances data;
private boolean sensitiveOption;
private Filter filter = new Discretize();
public DiscretizeFilter(Instances data, boolean sensitiveOption)
{
this.data = data;
this.sensitiveOption = sensitiveOption;
}
public Instances discreteFilter() throws Exception
{
NumericToNominal nm = new NumericToNominal();
nm.setInputFormat(data);
Filter.useFilter(data, nm);
Instances nominalData = nm.getOutputFormat();
if(sensitiveOption)//if the user wants extra sensitivity
{
String options[] = new String[1];
options[0] = options[0];
options[2] = "-E";
((Discretize) filter).setOptions(options);
}
filter.setInputFormat(nominalData);
Filter.useFilter(nominalData,filter);
return filter.getOutputFormat();
}
}
这是我的属性选择类:
import weka.attributeSelection.BestFirst;
import weka.attributeSelection.CfsSubsetEval;
import weka.core.Instances;
import weka.filters.supervised.attribute.AttributeSelection;
public class AttributeSelectionFilter
{
public Instances selectionFilter(Instances data) throws Exception
{
AttributeSelection filter = new AttributeSelection();
for(int i = 0; i < data.numInstances(); i++)
{
filter.input(data.instance(i));
}
CfsSubsetEval eval = new CfsSubsetEval();
BestFirst search = new BestFirst();
filter.setSearch(search);
filter.setEvaluator(eval);
filter.setInputFormat(data);
AttributeSelection.useFilter(data, filter);
return filter.getOutputFormat();
}
public int attributeCounter(Instances data)
{
return data.numAttributes();
}
}
任何帮助将不胜感激!!!
内部WEKA将属性值作为双倍存储。似乎引发了一个异常,因为数据集中的每个实例(data
)都"缺少类",即出于任何原因,都给出了内部类属性值NAN("非数字")。如果正确创建/设置data's
类属性,我建议双重检查。
我弄清楚了,这是我在离散类中误解方法" outputformat()"的描述的错误。相反,我从useFilter()中获得了过滤的实例,这解决了我的问题!我只是给出属性选择过滤错误的数据类型。