Question

I’m not sure if there is a more efficient way of doing what I’m doing using LINQ… I have two enumerations:

enumA(string): { "Andy", "Bill", "Charlie", "Doug" }
enumB(foo): { "Doug", "Edward", "George", "Bill" } (Note that enumB actually contains objects)

var dictionary = new Dictionary<string, 
foreach (var a in enumA)
{
    var b = enumB.SingleOrDefault(x => String.Equals(x.ToString(), a));

    if (b != null)
        dictionary[a] = b;
}

---

It just seems bad to me to enumerate over enumB over and over again and create a dictionary this way when I’m sure there is probably a more “correct” way to create a dictionary using LINQ.

Answer 1

You can do it efficiently using a

join

and an

ToDictionairy

call afterwards.

        var listA = "abcd";
        var listB = "cdef";

        var tuples = from charFromA in listA
                    join charFromB in listB
                    on charFromA.ToString() equals charFromB.ToString() // instead of ToString(), do something complex
                    select new { A = charFromA, B = charFromB };

        var dictionairy = tuples.ToDictionary(keySelector: t => t.A,elementSelector: t => t.B);