Any

Any is used to check if any element of a collection matches a condition or not. see also: .All, Any and FirstOrDefault: best practice

1. Empty parameter

Any: Returns true if the collection has any elements and false if the collection is empty:

var numbers = new List<int>();
bool result = numbers.Any(); // false

var numbers = new List<int>(){ 1, 2, 3, 4, 5};
bool result = numbers.Any(); //true

2. Lambda expression as parameter

Any: Returns true if the collection has one or more elements that meet the condition in the lambda expression:

var arrayOfStrings = new string[] { "a", "b", "c" };
arrayOfStrings.Any(item => item == "a");    // true
arrayOfStrings.Any(item => item == "d");    // false

3. Empty collection

Any: Returns false if the collection is empty and a lambda expression is supplied:

var numbers = new List<int>();
bool result = numbers.Any(i => i >= 0); // false

Note: Any will stop iteration of the collection as soon as it finds an element matching the condition. This means that the collection will not necessarily be fully enumerated; it will only be enumerated far enough to find the first item matching the condition.

Live Demo on .NET Fiddle