Enumeration Behaviour

gistfile1.txt

[Test]
        public void CollectionTests()
        {
            var letterList = new List<string>
            {
                "a","b"
            };

            IEnumerable<string> letters = letterList.Select(l =>
                {
                    var s = new String(l.ToCharArray());
                    Console.WriteLine("selecting");
                    return s;
                });

            foreach (var letter in letters)
                Console.WriteLine(letter);
        }