我的设备产生了一些异常数据，如何找到？-526互联

对于异常值检测，我们可以使用一种称为"3倍中位数绝对偏差（3 times Median Absolute Deviation，3*MAD）"的方法。

using System;
using System.Collections.Generic;
using System.Linq;

public class Program
{
    public static void Main(string[] args)
    {
        List<double> data = new List<double> { 0.1, 0.3, 0.27, 0.29, 18.7, 18.5, 0.3, 0.5, 0.9 };

        List<double> outliers = FindOutliers(data);

        Console.WriteLine("异常数据：");
        foreach (double outlier in outliers)
        {
            Console.WriteLine(outlier);
        }
    }

    public static List<double> FindOutliers(List<double> data)
    {
        List<double> outliers = new List<double>();

        double median = CalculateMedian(data);
        double mad = CalculateMAD(data, median);

        foreach (double value in data)
        {
            if (Math.Abs(value - median) > 3 * mad) // 判断是否为异常值，这里使用3倍MAD作为判断条件
            {
                outliers.Add(value);
            }
        }

        return outliers;
    }

    public static double CalculateMedian(List<double> data)
    {
        List<double> sortedData = data.OrderBy(x => x).ToList();
        int n = sortedData.Count;
        if (n % 2 == 0)
        {
            return (sortedData[(n / 2) - 1] + sortedData[n / 2]) / 2;
        }
        else
        {
            return sortedData[n / 2];
        }
    }

    public static double CalculateMAD(List<double> data, double median)
    {
        List<double> absoluteDeviations = new List<double>();
        foreach (double value in data)
        {
            absoluteDeviations.Add(Math.Abs(value - median));
        }

        double mad = CalculateMedian(absoluteDeviations);
        return mad;
    }
}

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