Use LINQ and C# to make a new List from an old List

Question

This should be pretty simple, but I am new at LINQ. I have a List of FillList structs. I\'d like to use LINQ to create a new

Answer 1

This will select all your data from the enumerable "fillstructs" and create an enumerable of "NewFillStruct" containing the calculated values.

 var newfills = from fillstruct in fillstructs
               select new NewFillStruct
               {
                   numlong = fillstruct.buy - fillstruct.sell,
                   date = fillstruct.date
               };

Answer 2

List<FillStruct> origList = ...
List<NewFillStruct> newList = origList.Select(x => new NewFillStruct {
    numlong = x.buy - x.sell, date = x.date
}).ToList();

However, note that struct is not necessarily a good choice for this (prefer class unless you have a good reason).

Or to avoid LINQ entirely:

List<NewFillStruct> newList = origList.ConvertAll(x => new NewFillStruct {
    numlong = x.buy - x.sell, date = x.date
});