C# Linq - Extract members of list within dictionary

Question

I have a use case for a dictionary like this one

var foo = new Dictionary<string, List<string>>()

so this collection will hold some hierarchical data like this

• Key 1
  • Value 1
  • Value 2
• Key 2
  • Value 3

and I need to get\project a list of values ignoring the keys, so result would be

• Value 1
• Value 2
• Value 3

on the first attempt I came up with this

IReadOnlyList<string> bar = foo.Select(r => r.Value.Select(x => x.ToString()))
                             .Select(r => r.ToString())
                             .ToList();

Is this any good?

Answer 1

Use SelectMany:

foo.SelectMany(x => x.Value).ToList();