转换字典 <Int, Object> 到字典 <Int, Object.Property> 与lambdas

Question

Suppose I have a class Building with properties int Id, int Height, int NumberOfFloors.

If I have a Dictionary, where each key is the building id. Is there a way to convert this into a Dictionary where each key is the building Id, and each value is the number of floors. Obviously this is feasible with a loop. Just wondering if there is a simple way to do this using lambdas?

Thanks!

var intToBuilding = new Dictionary<int, Building>(); //pretend populated
var intToInt = new Dictionary<int, int>();
foreach(var intBuilding in intToBuilding)
{
  var building = userPreference.Value;
  intToInt.Add(intBuilding.Key, building.Height);
} 

Answer 1

It should go something like:

var floorDictionary = buildingDictionary
   .ToDictionary(kv => kv.Key, kv => kv.Value.NumberofFloors);

The source dictionary implements IEnumerable< KeyValuePair<TKey, TValue> > and for that there is an extension method ToDictionary(keySelector, valueSelector) .