Predicate Delegates in C#

Question

Can you explain to me:

• What is a Predicate Delegate?
• Where should we use predicates?
• Any best practices when using predicates?

Answer 1

The predicate-based searching methods allow a method delegate or lambda expression to decide whether a given element is a “match.” A predicate is simply a delegate accepting an object and returning true or false: public delegate bool Predicate (T object);

   static void Main()
        {
            string[] names = { "Lukasz", "Darek", "Milosz" };
            string match1 = Array.Find(names, delegate(string name) { return name.Contains("L"); });
            //or
            string match2 = Array.Find(names, delegate(string name) { return name.Contains("L"); });
            //or
            string match3 = Array.Find(names, x => x.Contains("L"));


            Console.WriteLine(match1 + " " + match2 + " " + match3);     // Lukasz Lukasz Lukasz
        }
        static bool ContainsL(string name) { return name.Contains("L"); }