Get sum of the value from list using linq?

Question

I am trying to get the sum of the value from list of list using linq ?my data is as below code

        List> allData = new List<         


        

Answer 1

Not sure if you want to get the sum of every group or the total. If it's the total then this should do the trick

var sum = allData.Sum(x => Int32.Parse(x[2]));

If it's per key then try the following

var all = allData
  .GroupBy(x => x[0])
  .Select(x => x.Sum(y => Int32.Parse(y[2]));