using System;
using System.Collections.Generic;
using System.Linq;
 
public class Test
{
	public static void Main()
	{
        List<double> myDataList = new List<double> {1, 3, 14, 15, 22};
        double position = 2.2;
        var res = myDataList
            .Select((v, i) => new {Position = v, Index = i}) // Pair up the position and the index
            .OrderBy(p => Math.Abs(p.Position - position))            // Order by the distance
            .First().Index;  
        Console.WriteLine(res);
	}
}

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