Question

I have a list of objects like this:

List<ClassName> list = new List<ClassName>();
list.Add(new ClassName()
{
    Name = 1,
    Amount = 5
});
list.Add(new ClassName()
{
    Name = 2,
    Amount = 10
});
list.Add(new ClassName()
{
    Name = 1,
    Amount = 20
});
list.Add(new ClassName()
{
    Name = 3,
    Amount = 10
});
list.Add(new ClassName()
{
    Name = 3,
    Amount = 15
});

Now I would like to summarize this list by the property Name. The result should contain one entry for every Name and the sum of Amount of the entries with the same Name.
So this would be the expected result:

List<ClassName> list = new List<ClassName>();
list.Add(new ClassName()
{
    Name = 1,
    Amount = 25
});
list.Add(new ClassName()
{
    Name = 2,
    Amount = 10
});
list.Add(new ClassName()
{
    Name = 3,
    Amount = 25
});

How can I archive this?

Answer 1

 var lst = list.GroupBy(g = > g.Name).Select(t = > new
 ClassName()
 {
     Amount = t.Sum(s=>s.Amount), Name = t.Key
 }).ToList();