这段代码摘自这个教程，内容关于如何在Infer.NET库中使用学习器。我计划将其用于机器学习，但遗憾的是我无法理解这段代码片段。请帮助我解决这个问题。

/// <summary>/// Bayes Point Machine分类器教程的映射。/// </summary>public class ClassifierMapping     : IClassifierMapping<IList<Vector>, int, IList<string>, string, Vector>{    public IEnumerable<int> GetInstances(IList<Vector> featureVectors)    {        for (int instance = 0; instance < featureVectors.Count; instance++)        {            yield return instance;        }    }    public Vector GetFeatures(int instance, IList<Vector> featureVectors)    {        return featureVectors[instance];    }    public string GetLabel(        int instance, IList<Vector> featureVectors, IList<string> labels)    {        return labels[instance];    }    public IEnumerable<string> GetClassLabels(        IList<Vector> featureVectors = null, IList<string> labels = null)    {        return new[] { "Female", "Male" };    }}

提前感谢您！

回答：

唯一稍微复杂的部分是yield return：

public IEnumerable<int> GetInstances(IList<Vector> featureVectors){    for (int instance = 0; instance < featureVectors.Count; instance++)    {        yield return instance;    }}

可以替换为：

public IEnumerable<int> GetInstances(IList<Vector> featureVectors){    var result = new List<int>();    for (int instance = 0; instance < featureVectors.Count; instance++)    {       result.Add(instance);    }    return result;}