Question

I’m a big noob with Linq and trying to learn, but I’m hitting a blocking point here.
I have a structure of type:

Dictionary<MyType, List<MyObj>>

And I would like to query with Linq that structure to extract all the MyObj instances that appear in more than one list within the dictionary.

What would such a query look like?

Thanks.

Answer 1

from myObjectList in myObjectDictionary.Values
from myObject in myObjectList.Distinct()
group myObject by myObject into myObjectGroup
where myObjectGroup.Skip(1).Any()
select myObjectGroup.Key

The Distinct() on each list ensures MyObj instances which repeat solely in the same list are not reported.