using System; using static System.Console; using System.Collections.Generic; public class Program { public static void Main() { var list = new List() { "Leão", "Guepardo", "Elefante" }; var array = new string[3] { "Leão", "Guepardo", "Elefante" }; WriteLine(list.IndexOf("Elefante")); WriteLine(Array.IndexOf(array, "Elefante")); } } //https://pt.stackoverflow.com/q/321203/101