java - 使用arff文件存储数据

我正在使用此示例为我的weka projext enter link description here创建.arff文件。

double[][] data = {{4058.0, 4059.0, 4060.0, 214.0, 1710.0, 2452.0, 2473.0, 2474.0, 2475.0, 2476.0, 2477.0, 2478.0, 2688.0, 2905.0, 2906.0, 2907.0, 2908.0, 2909.0, 2950.0, 2969.0, 2970.0, 3202.0, 3342.0, 3900.0, 4007.0, 4052.0, 4058.0, 4059.0, 4060.0},
                       {19.0, 20.0, 21.0, 31.0, 103.0, 136.0, 141.0, 142.0, 143.0, 144.0, 145.0, 146.0, 212.0, 243.0, 244.0, 245.0, 246.0, 247.0, 261.0, 270.0, 271.0, 294.0, 302.0, 340.0, 343.0, 354.0, 356.0, 357.0, 358.0}};

    int numInstances = data[0].length;

    FastVector atts = new FastVector();
    ArrayList<Instance> instances = new ArrayList<Instance>();
    for (int dim = 0; dim < 2; dim++) {
        // Create new attribute / dimension
        Attribute current = new Attribute("Attribute" + dim, dim);
        // Create an instance for each data object


        if (dim == 0) {
            for (int obj = 0; obj < numInstances; obj++) {
                instances.add(new SparseInstance(0));

            }
        }

        // Fill the value of dimension "dim" into each object
        for (int obj = 0; obj < numInstances; obj++) {
            instances.get(obj).setValue(current, data[dim][obj]);
            System.out.println(instances.get(obj));
        }

        // Add attribute to total attributes
        atts.addElement(current);

    }

     // Create new dataset
    Instances newDataset = new Instances("Dataset", atts, instances.size());

    // Fill in data objects
    for (Instance inst : instances) {
        newDataset.add(inst);
    }

    BufferedWriter writer = new BufferedWriter(new FileWriter("test.arff"));
    writer.write(newDataset.toString());
    writer.flush();
    writer.close();
}

我注意到结果格式将row元素放入向量中
在.arff文件的列中。我想将整个行放在.arff文件的第一行中。我该怎么办？就我而言，2d向量的最后一列代表行数据的标签。

我的arff文件的预期结果：

4058.0, 4059.0, 4060.0, 214.0, 1710.0, 2452.0, 2473.0, 2474.0, 2475.0, 2476.0, 2477.0, 2478.0, 2688.0, 2905.0, 2906.0, 2907.0, 2908.0, 2909.0, 2950.0, 2969.0, 2970.0, 3202.0, 3342.0, 3900.0, 4007.0, 4052.0, 4058.0, 4059.0, 4060.0, 1 // for example the first row
 19.0, 20.0, 21.0, 31.0, 103.0, 136.0, 141.0, 142.0, 143.0, 144.0, 145.0, 146.0, 212.0,
 243.0, 244.0, 245.0, 246.0, 247.0, 261.0, 270.0, 271.0, 294.0, 302.0, 340.0, 343.0,
 354.0, 356.0, 357.0, 358.0, 0 // the second row.

最佳答案

该示例中的代码将表中的每一列都视为一个实例（因此，有29个实例，每个实例都有两个属性）。听起来您想将每一行都视为一个实例（给出两个实例，每个实例具有29个属性）：

double[][] data = {
                    {4058.0, 4059.0, ... }, /* first instance */
                    {19.0, 20.0, ... }      /* second instance */
                  };

int numAtts = data[0].length;
FastVector atts = new FastVector(numAtts);
for (int att = 0; att < numAtts; att++)
{
    atts.addElement(new Attribute("Attribute" + att, att));
}

int numInstances = data.length;
Instances dataset = new Instances("Dataset", atts, numInstances);
for (int inst = 0; inst < numInstances; inst++)
{
    dataset.add(new Instance(1.0, data[inst]));
}

BufferedWriter writer = new BufferedWriter(new FileWriter("test.arff"));
writer.write(dataset.toString());
writer.flush();
writer.close();

我将SparseInstance替换为Instance，因为几乎所有属性值都不为零。请注意，在Weka 3.7中，Instance已成为接口，应改为使用DenseInstance。另外，不建议使用FastVector来支持Java的ArrayList。

关于java - 使用arff文件存储数据，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/21723013/

Arff文件

java - 使用arff文件存储数据