public int CompareTo(object a)
{
KnnPoint p1 = a as KnnPoint;
if (this.Dist > p1.Dist)
{
return(1);
}
else if (this.Dist == p1.Dist)
{
return(0);
}
else
{
return(-1);
}
}
static void Main(string[] args)
{
StreamReader sr = File.OpenText("./data.txt"); // 数据文件
List <KnnPoint> pointList = new List <KnnPoint>(); // 训练数据点
KnnPoint pt = new KnnPoint(0.9, 0.8, .0, ""); // 待判断点
int k = 4; // k值
double distance = .0;
List <string> labels = new List <string>(); // 用于保存所有标签
List <LabelCount> lc = new List <LabelCount>(); // 标签、计数,方便排序
// 读取文件，获取标签和点
string line; // 保存一行
string[] d; // 一行中分割后的数据
while (!sr.EndOfStream)
{
line = sr.ReadLine();
d = line.Split(' ');
distance = Math.Sqrt(Math.Pow(double.Parse(d[0]) - pt.X, 2) + Math.Pow(double.Parse(d[1]) - pt.Y, 2)); // 计算距离
pointList.Add(new KnnPoint(double.Parse(d[0]), double.Parse(d[1]), distance, d[2]));
// 发现有哪些标签
if (!labels.Contains(d[2]))
{
labels.Add(d[2]);
lc.Add(new LabelCount(d[2], 0));
}
}
pointList.Sort(); // 根据距离，对所有点排序
// 选取前k个点
for (int i = 0; i < k; i++)
{
lc[labels.IndexOf(pointList[i].Label)].Count++;
// 与下面代码等价
//index = labels.IndexOf(pointList[i].Label);
//lc[index].Count++;
}
lc.Sort();
// 决定属于哪一类
Console.WriteLine("未知点属于" + lc[labels.Count - 1].Label + "类");
}