Convert nested list to 2d array

Question

I\'m trying to convert a nested list into a 2d array.

List> list = new ArrayList<>();

list.add(Arrays.asList(\"a\", \"b\", \"         


        

Answer 1

You could do this:

String[][] array = list.stream()
    .map(l -> l.stream().toArray(String[]::new))
    .toArray(String[][]::new);

It creates a Stream> from your list of lists, then from that uses map to replace each of the lists with an array of strings which results in a Stream, then finally calls toArray(with a generator function, instead of the no-parameter version) on that to produce the String[][].