I have this class.
class Assignment {
private Integer index;
private List<Quantity> quantities;
}
Then, I have a list of objects from that class.
List<Assigment> assignments = new ArrayList<>();
Is there a way to create a Map
that contains the index from Assignment
and the List<Quantity>
as values?
This is what I have tried so far.
assignments.stream().collect(groupingBy(Assignment::getIndex));
But this gives me a Map<Integer, List<Assignment>>
and I want a Map<Integer, List<Quantity>>
.
I have tried using forEach
method - and it workes - but I'm sure there must be a way to do it in one liner - or at least using only collect
and groupingBy
methods