Most efficient way to find if a value exists within a C# List [duplicate]

Question

In C# if I have a List of type bool. What is the fastest way to determine if the list contains a true value? I don’t need to know how many or where the true value is. I just need to know if one exists. I will be searching many extremely large lists.

Answer 1

Just use bool trueInList = list.Contains(true);. This loops the list until there's a true.

Why do you need something faster with such a simple use-case?

Answer 2

Use either list.Contains(true) or list.Any(true). For a normal list both have complexity O(n). Since Any() is an extension method though, which needs to invoke delegates, the Contains() might still be a bit faster. But to be sure I would simply test both with a large collection.

Answer 3

You could use Any().

list.Any(b => b);

Answer 4

Try this:

var result = myBoolList.Any(i => i==true);

Answer 5

You use the Any(...)

list.Any(c => c == true);

or just

list.Any(c => c);

Answer 6

You can use BinarySearch method of the list.

if(list.BinarySearch(true) > 0){...}