Question

I have a List. I want to know how to write LINQ or so to find if their exists an obj of MyTypes whose id = “CLR”.

I would like to know if it exists and its index. So if it exists, then thru its index I can replace with a new object of MyTypes else add it.

I know I cna do it thru iterating the items in List, but that will be time consuming than using LINQ statement. Correct me if am wrong.

Can any provide help.

Answer 1

You don’t really need LINQ for this; there’s the handy List<T>.FindIndex method

List<Foo> foos = ...
int index = foos.FindIndex(foo => foo != null && foo.Id == "CLR");

if(index != -1)
{
     Foo replacement = ...
     foos[index] = replacement;
}
else
{
     Foo toAdd = ...
     foos.Add(toAdd);
}

By the way, are you sure you don’t actually need a lookup-table of some sort? Your usage pattern suggests you wan’t a Dictionary<string, Foo> or similar rather than a list.