Is it possible for me to use LINQ in a way that allows me to determine that \"9\" is the first missing value in the sorted list without using a for-loop and comparing each
Let
var strings = new string[] { "7", "13", "8", "12", "10", "11", "14" };
Then
var list = Array.ConvertAll(strings, s => Int32.Parse(s)).OrderBy(i => i);
// or
var list = strings.Select(s => int.Parse(s)).OrderBy(i => i);
// or
var list = strings.OrderBy(s => int.Parse(s));
(note this question)
and then
var result = Enumerable.Range(list.Min(), list.Count).Except(list).First(); // 9
// or
int min = list.Min(), max = list.Max();
var result = Enumerable.Range(min, max - min + 1).Except(list).First();