如何在嵌套ArrayList（ArrayList的ArrayList）中打开Array？

Question

I had to turn nested ArrayList

 List<List<TockaXY>> clustersPorazdeljeni = new ArrayList<>(center.size()) 

in to Array, witch with help of nice people from this site is now clear:

TockaXY[] arrayOfClusters = clustersPorazdeljeni.stream().flatMap(Collection::stream).toArray(TockaXY[]::new);

But I have to also do the reverse. So how to get from arrayOfClusters back an nested ArrayList like

List<List<TockaXY>> newClustersPorazdeljeni 

?

Answer 1

You have asked vice versa question today. How to convert nested ArrayList in Array?

TockaXY[] arrayOfClusters this is flat array and there is no mark how to split it to a few arrays. Maybe you should to do the convertation to another data structure not in TockaXY[], to map en example.