Hello Sebastian, You can use DataSet.leftOuterJoin for this.
Best, Gábor 2017-02-10 12:58 GMT+01:00 Sebastian Neef <gehax...@mailbox.tu-berlin.de>: > Hi, > > is it possible to assign a "default" value to elements that didn't match? > > For example I have the following two datasets: > > |DataSetA | DataSetB| > --------------------- > |id=1 | id=1 > |id=2 | id=3 > |id=5 | id=4 > |id=6 | id=6 > > When doing a join with: > > A.join(B).where( KeySelector(A.id)) > .equalTo(KeySelector(B.id)) > > The resulting dataset is: > > |(DataSetA | DataSetB)| > --------------------- > |(id=1 | id=1) > |(id=6 | id=6) > > What is the best way to assign a default value to the elements id=2/id=5 > from DataSet A. E.g. I need a result which looks similar to this: > > |(DataSetA | DataSetB)| > --------------------- > |(id=1 | id=1) > |(id=2 | Default) > |(id=5 | Default) > |(id=6 | id=6) > > My idea would be to get the missing Elements from DataSetA by .filter > with (DataSetA|DataSetB) and then do a .union after creating a tuple > with a default value. But that sounds a bit over-complicated. > > Best regards, > Sebastian