C# IQR算法检测异常点

话不多说，上马

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

            double q1 = GetQuantile(data, 0.25);
            double q3 = GetQuantile(data, 0.75);
            double iqr = q3 - q1;
            double lowerBound = q1 - 1.5 * iqr;
            double upperBound = q3 + 1.5 * iqr;
            foreach (double value in data)
            {
                if (value < lowerBound || value > upperBound)
                {
                    outliers.Add(value);
                }
            }
            return outliers;
        }
        // 计算指定百分位数的值
        private double GetQuantile(List<double> data, double percentile)
        {
            data.Sort();
            int count = data.Count;
            double index = percentile * (count - 1);
            int floor = (int)Math.Floor(index);
            int ceil = (int)Math.Ceiling(index);

            if (floor == ceil)
            {
                return data[floor];
            }
            else
            {
                double lowerValue = data[floor] * (ceil - index);
                double upperValue = data[ceil] * (index - floor);
                return lowerValue + upperValue;
            }
        }
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使用

 List<double> datas = new List<double>() {1,3,0,2,4,1,6,8,22,5,6,7,33,5,1,99,55,5,9,8,7 };
            List<double> temps = DetectOutliersIQR(datas);
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异常检测结果