Filter list contents with predicate (Lambda)
using System;
using System.Collections.Generic;
var words = new List<string> { "falcon", "wood", "tree",
"rock", "cloud", "rain" };
Predicate<string> hasFourChars = word => word.Length == 4;
var words2 = words.FindAll(hasFourChars);
Console.WriteLine(string.Join(',', words2));