[c#] conditional Updating a list using LINQ

I had a list

List<Myclass> li = new List<Myclass>();

where Myclass is

class Myclass
{
public string name {get;set;}
public decimal age {get;set;}
}

items in li looks like

 i want to update `li` according to name but with `LINQ` like

li.where(w=> w.name = "di") = li.Where(w => w.name =="di").select(s => {s.age = 10;return s;}).Tolist();
li.where(w=> w.name = "marks") = li.Where(w => w.name =="marks").select(s => {s.age = 20;return s;}).Tolist();
li.where(w=> w.name = "grade") = li.Where(w => w.name =="grade").select(s => {s.age = 10;return s;}).Tolist();

and want result which looks like this

my code gives error can you please tell how i do this

How about

(from k in myList
 where k.id > 35
 select k).ToList().ForEach(k => k.Name = "Banana");

Try Parallel for longer lists:

Parallel.ForEach(li.Where(f => f.name == "di"), l => l.age = 10);

        li.Where(w => w.name == "di" )
          .Select(s => { s.age = 10; return s; })
          .ToList();

You need:

li.Where(w=> w.name == "di").ToList().ForEach(i => i.age = 10);

Program code:

namespace Test
{
    class Program
    {
        class Myclass
        {
            public string name { get; set; }
            public decimal age { get; set; }
        }

        static void Main(string[] args)
        {
            var list = new List<Myclass> { new Myclass{name = "di", age = 0}, new Myclass{name = "marks", age = 0}, new Myclass{name = "grade", age = 0}};
            list.Where(w=> w.name == "di").ToList().ForEach(i => i.age = 10);
            list.ForEach(i => Console.WriteLine(i.name + ":" + i.age));
        }
    }
}

Output:

 di:10
 marks:0
 grade:0

Try this:

li.ForEach(x => x.age = (x.name == "di") ?
                10 : (x.name == "marks") ?
                20 : (x.name == "grade") ?
                30 : 0 );

All values are updated in one line of code and you browse the List only ONE time. You have also a way to set a default value.

If you really want to use linq, you can do something like this

li= (from tl in li
    select new Myclass
    {
        name = tl.name,
        age = (tl.name == "di" ? 10 : (tl.name == "marks" ? 20 : 30))

    }).ToList();

or

li = li.Select(ex => new MyClass { name = ex.name, age = (ex.name == "di" ? 10 : (ex.name == "marks" ? 20 : 30)) }).ToList();

This assumes that there are only 3 types of name. I would externalize that part into a function to make it more manageable.