Question

I am currently building a data structure which relies a lot on efficiency.

Can anyone provide me with resources on how the Find(item => item.X = myObject.Property) method actually works?
Does it iterate linearly throughout all elements until it finds the element?

And what if I know the index of myObject and I use ElementAt(index)?

Which will be the most efficient of these two please?

Answer 1

From the MSDN documentation on List<T>.Find

This method performs a linear search; therefore, this method is an O(n) operation, where n is Count.

I imagine that ElementAt is optimized for IList and will do a direct index. But since you’re apparently using this object from the List concrete type anyway, why not just do a direct index? Like this:

var result = list[index];

If you already know the index, there is no point to searching. Just go straight to it.