Question

Can somebody suggest me what Linq operator should I use to write an elegant code to convert List to Dictionary of list?
Eg. I have a list of person (List<Person>) and I wanted to convert that to dictionary of list (like Dictionary<string, List<Person>> using the person’s last name as a key. I needed that for quickly lookup the list of persons by the last name

Answer 1

To get a Dictionary<string, List<Person>> from List<Person>:

var dictionary = list
                   .GroupBy(p => p.LastName)
                   .ToDictionary(g => g.Key, g => g.ToList());