using System;

using System.Collections.Generic;

​

public class Program

{

    public static void Main()

    {

        var rules = new List<string> { "Hello", "World", "Foo", "Bar" };

        foreach (var rule in rules)

        {

            string place;

            if ((place = GetPlace(rule)) != null)

            {

                Console.WriteLine($"Found {place}");

            }

        }

    }

    static string GetPlace(string rule)

    {

        if (rule == "Hello")

            return "hey";

        if (rule == "World")

            return "mundo";

        return null;

    }

}

​