Get the return list from foreach Java 8

I'm trying to use stream to deal with something. I think I have a conceptual misunderstanding I try to get an array, convert it into a stream, and put it in the array Foreach item I want to run a function and return a list of the results of the function from foreach

Basically this:

Thing[] functionedThings = Array.stream(things).forEach(thing -> functionWithReturn(thing))

Is that possible? Do I use the wrong streaming function?

Solution

You are looking for a map operation:

Thing[] functionedThings = Arrays.stream(things).map(thing -> functionWithReturn(thing)).toArray(Thing[]::new);

This method is used to map an object to another object; Reference Javadoc, which says it's better:

Note that the toArray (generator) method is used to convert the stream back to an array; The generator used is a function (which is actually a method reference) that returns a new array of things