How do you get the index of a number in a linked list?

Question

I have a linked list constructed as follows:

LinkedList linked = new LinkedList();
var array = new int[] { 23, 55, 64, 65 };
foreach (         


        

Answer 1

Here is an alternate LINQ implementation that avoids creating anonymous objects and returns -1 if the item is not in the list:

int index = linked.Select((n, i) => n == 64 ? (int?)i : null).
            FirstOrDefault(n => n != null) ?? -1;

It converts the sequence of numbers to a sequence containing the index of a match or null otherwise. It takes the first of these if there is one, otherwise converts the default int? to -1.

Edit:

Here is a better (simpler and more performant) alternative:

int i = linked.TakeWhile(n => n != 64).Count();

i will either be equal to the index, or equal to linked.Count if the value 64 was not found.