Is there a LINQ function for getting the longest string in a list of strings?

This will do it with only one loop iteration:

list.Aggregate("", (max, cur) => max.Length > cur.Length ? max : cur);

var list = new List<string>(); // or string[] or any

list.Add("a");
list.Add("ccc");
list.Add("bb");
list.Add("eeeee");
list.Add("dddd");

// max-length
var length = list.Max(s => s.Length);

// biggest one
var biggest = list.FirstOrDefault(s => s.Length == length);

// if there is more that one by equal length
var biggestList = list.Where(s => s.Length == length);

// by ordering list
var biggest = list.OrderByDescending(s => s.Length).FirstOrDefault();

// biggest-list by LINQ
var bigList2 = from s in list where s.Length == list.Max(a => a.Length) select s;

// biggest by LINQ
var biggest2 = bigList2.FirstOrDefault();

You can use this: list.OrderByDescending(s => s.Length).First();