Using a function in Java8 map

Question

Is there a Java8 equivalent way of writing the following?

List<Foo> results = new ArrayList<>();
for (RowResult row : rows) {
   results.add(rowToFooFunction(classroomLookup.get(row.getId()), studentLookup.get(row.getId())).apply(row));
}

Where the rowToFooFunction is like Function<RowResult, Foo> rowToFoo (Classroom c, Student s)...

So I would like to end up with something like:

rows.stream.map(rowToFooFunction...).collect(Collectors.toList());

The problem is, in the map step, I need to lookup the student/classroom by the id of the row i am iterating over.

@SotiriosDelimanolis I'm sorry, what?

John Baum
– John Baum

2016-09-02 01:30:15 +00:00
Commented Sep 2, 2016 at 1:30 — John Baum
– John Baum, Commented Sep 2, 2016 at 1:30

sebnukem · Accepted Answer · 2016-09-02 01:38:56Z

3

You almost found the solution yourself already, you are very close:

List<Foo> results = rows.stream().map(row ->
  rowToFooFunction(classroomLookup.get(row.getId()), studentLookup.get(row.getId())).apply(row))
).collect(Collectors.toList());

edited Sep 2, 2016 at 1:38

answered Sep 2, 2016 at 1:33

sebnukem

8,3536 gold badges40 silver badges49 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Using a function in Java8 map

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related