c# calculate standard deviation to achieve the same STDEVP() as in excel

Foreword: The Compute method in the DataTable written in this blog uses the STDEV method , but there is no STDEVP method. Sorrowful. What if the customer requires STDEVP. I searched a lot on the Internet, and one wrote what I wanted. Summarize here!
First on a StDev:

string  StDevValue= table.Compute("StDev(field)", "field>0");

Probably like this.
STDEVP:

DataRow[] ddr = data.Select(dt2.Rows[j]["field"].ToString() + " is not null ");
double[] array = new double[ddr.Length];
int di = 0;
foreach (DataRow ddrs in ddr)
{
    
    
	array[di] = Convert.ToDouble(ddrs[dt2.Rows[j]["field"].ToString()]);
	di++;
}
	double stdDev = CalculateStdDev(array);
	dr[dt2.Rows[j]["field"].ToString()] = stdDev;

The above piece of code is what I need. Too lazy to organize. Take a look; you adjust the
main part yourself according to your needs

		private static double CalculateStdDev(IEnumerable<double> values)
        {
    
    
            double ret = 0;
            if (values.Count() > 0)
            {
    
    
                //  计算平均数   
                double avg = values.Average();
                //  计算各数值与平均数的差值的平方，然后求和 
                double sum = values.Sum(d => Math.Pow(d - avg, 2));
                //  除以数量，然后开方
                ret = Math.Sqrt(sum / values.Count());
            }
            return ret;
        }

Mainly this is over. Thanks everyone