Java8 Lambda: concat list [duplicate]

Question

I am trying to concat list of a stream and process it.

class A {
    public List<B> bList;
}
List<A> aList;
aList.stream().map(a -> a.bList)....

Here i get several list of b.

But, I would like to collect all my b in only one list. Any ideas ?

Eran · Accepted Answer · 2015-01-07 10:14:00Z

18

That's what flatMap is for :

List<B> bList = aList.stream()
                     .flatMap(a -> a.bList.stream())
                     .collect(Collectors.toList());

answered Jan 7, 2015 at 10:14

Eran

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