Calculate difference from previous item with LINQ

Question

I\'m trying to prepare data for a graph using LINQ.

The problem that i cant solve is how to calculate the \"difference to previous.

the result I expect is <

Answer 1

Use index to get previous object:

   var LinqList = list.Select( 
       (myObject, index) => 
          new { 
            ID = myObject.ID, 
            Date = myObject.Date, 
            Value = myObject.Value, 
            DiffToPrev = (index > 0 ? myObject.Value - list[index - 1].Value : 0)
          }
   );