using System;

using System.Linq;

using System.Collections.Generic;

​

public class Program

{

   public static void Main()

   {

      var data = new List<SummaryTabData>()

      {

         new() { LP = "LP_1", assetClass = "Asset_CFD_Long", avgSlippagePts = 54.23 },

         new() { LP = "LP_1", assetClass = "Asset_FX_Long", avgSlippagePts = 61.41 },

         new() { LP = "LP_1", assetClass = "Asset_FX_Short", avgSlippagePts = 11.48 },

         new() { LP = "LP_1", assetClass = "Asset_CFD_Short", avgSlippagePts = 63.51 },

​

         new() { LP = "LP_2", assetClass = "Asset_FX_Long", avgSlippagePts = 6.51 },

         new() { LP = "LP_2", assetClass = "Asset_FX_Short", avgSlippagePts = 13.51 }

      };

​

      data = data

         .OrderBy(x => x.LP)

         .ThenByDescending(x => x.assetClass).ToList();

​

      var results = data

         .Select(x => new { Asset = x.assetClass.Split("_")[1], Summary = x })

         .ToList();

​

      var groups = results

         .GroupBy(x => new { x.Asset, x.Summary.LP });

​

​

      foreach (var group in groups)

      {

         var bob = group.Last();

         var index = data.IndexOf(bob.Summary);

         data.Insert(index + 1,

            new SummaryTabData()

            {

               assetClass = $"{bob.Asset}_Total",

               LP = group.Key.LP,

               avgSlippagePts = group.Sum(x => x.Summary.avgSlippagePts)

            }

         );

      }

​

      foreach (var item in data)

         Console.WriteLine($"{item.LP}, {item.assetClass}, {item.avgSlippagePts}");

   }

}

​

public class SummaryTabData

{

   public string LP { get; set; }

   public string assetClass { get; set; }

   public double avgSlippagePts { get; set; }

}