如何从 arff 文件中删除特定属性并生成修改后的 arff？

Question

（非手动）我有 96 个特征，想从 arff 中删除大约 20 个特征并生成修改后的 arff。使用 weka 进行特征选择现在想删除那些不太重要的特征。谁能为此建议代码

Answer 1

给你...只需更改源文件路径和目标文件路径...

import java.io.File;
import weka.core.Instances;
import weka.core.converters.ArffLoader;
import weka.core.converters.ArffSaver;
import weka.filters.Filter;
import weka.filters.unsupervised.attribute.Remove;


public class Convert4 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        try
        {
            ArffLoader loader2= new ArffLoader();
            loader2.setSource(new File("C:/Users/RAHUL/Desktop/stack.arff"));
            Instances data2= loader2.getDataSet();
            //Load Arff
             String[] options = new String[2];
             options[0] = "-R";                                    // "range"
             options[1] = "1";                                     // first attribute
             Remove remove = new Remove();                         // new instance of filter
             remove.setOptions(options);                           // set options
             remove.setInputFormat(data2);                          // inform filter about dataset **AFTER** setting options
             Instances newData2 = Filter.useFilter(data2, remove);   // apply filter
             ArffSaver saver = new ArffSaver();
             saver.setInstances(newData2);
             saver.setFile(new File("C:/Users/RAHUL/Desktop/stack2.arff"));
             saver.writeBatch();
}
catch (Exception e)
{}
}
}

干杯:)

Answer 2

这里有简短的答案，请查看

BufferedReader datafile = new BufferedReader(new FileReader("bbcsport.arff")); 
BufferedReader attrfile = new BufferedReader(new FileReader("attributes.txt"));


Instances data = new Instances(datafile); 
List<Integer> myList = new ArrayList<Integer>();
String line;

while ((line = attrfile.readLine()) != null) {
  for (n = 0; n < data.numAttributes(); n++) {
    if (data.attribute(n).name().equalsIgnoreCase(line)) {
      if(!myList.contains(n)) 
        myList.add(n); 
    } 
  }
}

int[] attrs = myList.stream().mapToInt(i -> i).toArray();
Remove remove = new Remove();
remove.setAttributeIndicesArray(attrs);
remove.setInvertSelection(false);
remove.setInputFormat(data); // init filter

Instances filtered = Filter.useFilter(data, remove);

如何从 arff 文件中删除特定属性并生成修改后的 arff？

How to remove particular attributes from arff file and produce modified arff?

feature-extraction

arff

feature-selection